diff --git a/modules/binding-ws-axis2/src/test/java/org/apache/tuscany/sca/binding/ws/axis2/itests/mtom/FileTransferService.java b/modules/binding-ws-axis2/src/test/java/org/apache/tuscany/sca/binding/ws/axis2/itests/mtom/FileTransferService.java
index ab7fc9c..d617047 100644
--- a/modules/binding-ws-axis2/src/test/java/org/apache/tuscany/sca/binding/ws/axis2/itests/mtom/FileTransferService.java
+++ b/modules/binding-ws-axis2/src/test/java/org/apache/tuscany/sca/binding/ws/axis2/itests/mtom/FileTransferService.java
@@ -38,9 +38,12 @@
     public String uploadDataHandlerFile(DataHandler attachment) throws Exception;    
     
     public String uploadOMElementFile(OMElement attachment) throws Exception;
-    
+
+    // TUSCANY-3805: produces WSDL generation error with fix for TUSCANY-3298
+    /*
     //This method uses an user defined interface MyException as parameter type.
     public String sendMyException(@XmlJavaTypeAdapter(MyExceptionAdapter.class) MyException attachment) 
     																				throws Exception;
+    */
 }
 
diff --git a/modules/binding-ws-wsdlgen/src/main/java/org/apache/tuscany/sca/binding/ws/wsdlgen/Interface2WSDLGenerator.java b/modules/binding-ws-wsdlgen/src/main/java/org/apache/tuscany/sca/binding/ws/wsdlgen/Interface2WSDLGenerator.java
index a55670e..5425171 100644
--- a/modules/binding-ws-wsdlgen/src/main/java/org/apache/tuscany/sca/binding/ws/wsdlgen/Interface2WSDLGenerator.java
+++ b/modules/binding-ws-wsdlgen/src/main/java/org/apache/tuscany/sca/binding/ws/wsdlgen/Interface2WSDLGenerator.java
@@ -344,7 +344,8 @@
         // call each helper in turn to populate the wsdl.types element
         XmlSchemaCollection schemaCollection = new XmlSchemaCollection(); 
 
-        for (Map.Entry<XMLTypeHelper, List<DataType>> en: getDataTypes(interfaze, false, helpers).entrySet()) {
+        // TUSCANY-3298: enable JAXB wrapper generation
+        for (Map.Entry<XMLTypeHelper, List<DataType>> en: getDataTypes(interfaze, true, helpers).entrySet()) {
             XMLTypeHelper helper = en.getKey();
             if (helper == null) {
                 continue;
@@ -1112,6 +1113,11 @@
                                                dataType.getLogical());
         ElementInfo element = new ElementInfo(name, typeInfo);
         element.setMany(byte[].class != javaType && javaType.isArray());
+        // TUSCANY-3298: Check the "many" flag set by databinding introspection
+        Object logical = dataType.getLogical();
+        if (logical instanceof XMLType && ((XMLType)logical).isMany()) {
+            element.setMany(true);
+        }
         element.setNillable(!javaType.isPrimitive());
         return element;
     }
diff --git a/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Input2InputTransformer.java b/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Input2InputTransformer.java
index f537dc4..0d12d2b 100644
--- a/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Input2InputTransformer.java
+++ b/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Input2InputTransformer.java
@@ -121,13 +121,29 @@
         for (int i = 0; i < list1.size(); i++) {
             String n1 = list1.get(i).getQName().getLocalPart();
             String n2 = list2.get(i).getQName().getLocalPart();
-            if (!n1.equals(n2)) {
+
+            // TUSCANY-3298: In the following situation:
+            //  1. The child is a java.util.Map type
+            //  2. The child's name is a Java keyword (e.g., return)
+            //  3. Tuscany is using a generated JAXB wrapper class for WSDL generation
+            // the Java to WSDL generation process results in the WSDL element name
+            // having a leading underscore added to the actual element name.  This is
+            // because of a known JAXB issue that prevents the @XmlElement annotation
+            // being used on a java.util.Map type property field in the wrapper bean
+            // (see https://jaxb.dev.java.net/issues/show_bug.cgi?id=268).
+            // To prevent the compatibility match from failing in this situation,
+            // we strip any leading underscore before doing the comparison.
+            if (!stripLeadingUnderscore(n1).equals(stripLeadingUnderscore(n2))) {
                 return false;
             }
         }
         return true;
     }
 
+    private static String stripLeadingUnderscore(String name) {
+        return name.startsWith("_") ? name.substring(1) : name;
+    }
+
     @SuppressWarnings("unchecked")
     public Object[] transform(Object[] source, TransformationContext context) {
         // Check if the source operation is wrapped
diff --git a/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Output2OutputTransformer.java b/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Output2OutputTransformer.java
index 348d834..41285a9 100644
--- a/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Output2OutputTransformer.java
+++ b/modules/core-databinding/src/main/java/org/apache/tuscany/sca/core/databinding/transformers/Output2OutputTransformer.java
@@ -142,13 +142,29 @@
         for (int i = 0; i < list1.size(); i++) {
             String n1 = list1.get(i).getQName().getLocalPart();
             String n2 = list2.get(i).getQName().getLocalPart();
-            if (!n1.equals(n2)) {
+
+            // TUSCANY-3298: In the following situation:
+            //  1. The child is a java.util.Map type
+            //  2. The child's name is a Java keyword (e.g., return)
+            //  3. Tuscany is using a generated JAXB wrapper class for WSDL generation
+            // the Java to WSDL generation process results in the WSDL element name
+            // having a leading underscore added to the actual element name.  This is
+            // because of a known JAXB issue that prevents the @XmlElement annotation
+            // being used on a java.util.Map type property field in the wrapper bean
+            // (see https://jaxb.dev.java.net/issues/show_bug.cgi?id=268).
+            // To prevent the compatibility match from failing in this situation,
+            // we strip any leading underscore before doing the comparison.
+            if (!stripLeadingUnderscore(n1).equals(stripLeadingUnderscore(n2))) {
                 return false;
             }
         }
         return true;
     }
 
+    private static String stripLeadingUnderscore(String name) {
+        return name.startsWith("_") ? name.substring(1) : name;
+    }
+
     @SuppressWarnings("unchecked")
     public Object transform(Object response, TransformationContext context) {
         try {
diff --git a/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextHelper.java b/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextHelper.java
index d129ae6..7e42c66 100644
--- a/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextHelper.java
+++ b/modules/databinding-jaxb/src/main/java/org/apache/tuscany/sca/databinding/jaxb/JAXBContextHelper.java
@@ -24,8 +24,10 @@
 import java.lang.reflect.TypeVariable;
 import java.lang.reflect.WildcardType;
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 
 import javax.xml.bind.JAXBContext;
@@ -343,29 +345,54 @@
         WrapperInfo inputWrapperInfo = op.getInputWrapper();
         WrapperInfo outputWrapperInfo = op.getOutputWrapper();
         
+        // TUSCANY-3298: Add the wrapper type instead of individual elements
+        // if possible.  JAXB will implicitly add all types that are statically
+        // reachable from the wrapper class, with the exception of type arguments
+        // for parameterized types that aren't collections.
+        DataType dt1 = null;
         if (useWrapper && (inputWrapperInfo != null)) {
-            DataType dt1 = inputWrapperInfo.getWrapperType();
+            dt1 = inputWrapperInfo.getWrapperType();
             if (dt1 != null) {
                 dataTypes.add(dt1);
+                for (DataType in : op.getInputType().getLogical()) {
+                    if (isParameterizedNonCollectionType(in)) {
+                        // JAXB won't add the type arguments, so we need to add them
+                        dataTypes.add(in);
+                    }
+                }
             }
         }
+        if (dt1 == null) {
+            // We couldn't add the wrapper, so add the elements individually
+            for (DataType dt : op.getInputType().getLogical()) {
+                dataTypes.add(dt);
+            }
+        }
+
+        // TUSCANY-3298: Add the wrapper type instead of the output type
+        // if possible.  JAXB will implicitly add all types that are statically
+        // reachable from the wrapper class, with the exception of type arguments
+        // for parameterized types that aren't collections or maps.
+        DataType dt2 = null;
         if (useWrapper && (outputWrapperInfo != null)) {
-            DataType dt2 = outputWrapperInfo.getWrapperType();
+            dt2 = outputWrapperInfo.getWrapperType();
+            if (dt2 != null) {
+                dataTypes.add(dt2);
+                DataType out = op.getOutputType();
+                if (out != null && isParameterizedNonCollectionType(out)) {
+                    // JAXB won't add the type arguments, so we need to add them
+                    dataTypes.add(out);
+                }
+            }
+        }
+        if (dt2 == null) {
+            // We couldn't add the wrapper, so add the output type directly
+            dt2 = op.getOutputType();
             if (dt2 != null) {
                 dataTypes.add(dt2);
             }
         }
-        // FIXME: [rfeng] We may need to find the referenced classes in the child types
-        // else 
-        {
-            for (DataType dt1 : op.getInputType().getLogical()) {
-                dataTypes.add(dt1);
-            }
-            DataType dt2 = op.getOutputType();
-            if (dt2 != null) {
-                dataTypes.add(dt2);
-            }
-        }
+
         for (DataType<DataType> dt3 : op.getFaultTypes()) {
             DataType dt4 = dt3.getLogical();
             if (dt4 != null) {
@@ -374,6 +401,23 @@
         }
     }
 
+    /*
+     * We need to add parameterized non-collection types to the JAXB context
+     * explicitly, because type argument information for these types is erased
+     * from the generated wrapper bean. 
+     */
+    private static boolean isParameterizedNonCollectionType(DataType dt) {
+        Type type = dt.getGenericType();
+        if (type instanceof ParameterizedType) {
+            Class physical = dt.getPhysical();
+            if (!Collection.class.isAssignableFrom(physical) &&
+                !Map.class.isAssignableFrom(physical)) {
+                return true;
+            }
+        }
+        return false;
+    }
+
     @SuppressWarnings("unchecked")
     public static Class<?> getJavaType(DataType<?> dataType) {
         if (dataType == null) {
diff --git a/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDODataBinding.java b/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDODataBinding.java
index 39e9ffc..8e00a20 100644
--- a/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDODataBinding.java
+++ b/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDODataBinding.java
@@ -19,8 +19,10 @@
 
 package org.apache.tuscany.sca.databinding.sdo;
 
+import java.lang.reflect.ParameterizedType;
 import java.security.AccessController;
 import java.security.PrivilegedAction;
+import java.util.Collection;
 
 import javax.xml.namespace.QName;
 
@@ -60,7 +62,7 @@
 
     @Override
     public boolean introspect(DataType dataType, final Operation operation) {
-        final Class javaType = dataType.getPhysical();
+        Class javaType = dataType.getPhysical();
         // Allow privileged access to read system properties. Requires PropertyPermission
         // java.specification.version read in security policy.
         final HelperContext context = AccessController.doPrivileged(new PrivilegedAction<HelperContext>() {
@@ -72,11 +74,33 @@
         final Type type = context.getTypeHelper().getType(javaType);
         if (type == null) {
             // FIXME: Need a better to test dynamic SDO
+            // TUSCANY-3298: get underlying element type for collections
+            boolean isMany = false;
+            if (Collection.class.isAssignableFrom(javaType)) {
+                java.lang.reflect.Type genericType = dataType.getGenericType();
+                if (genericType instanceof ParameterizedType) {
+                    java.lang.reflect.Type actualType = ((ParameterizedType)genericType).getActualTypeArguments()[0];
+                    if (actualType instanceof Class) {
+                        javaType = (Class)actualType;
+                        isMany = true;
+                    }
+                }
+            }
             if (DataObject.class.isAssignableFrom(javaType)) {
                 // Dynamic SDO
                 dataType.setDataBinding(getName());
-                if (dataType.getLogical() == null) {
-                    dataType.setLogical(XMLType.UNKNOWN);
+                // TUSCANY-3298: use XMLType many value to indicate a collection
+                Object logical = dataType.getLogical();
+                if (logical == null) {
+                    if (!isMany) {
+                        dataType.setLogical(XMLType.UNKNOWN);
+                    } else {
+                        XMLType xmlType = new XMLType(null, null);
+                        xmlType.setMany(true);
+                        dataType.setLogical(xmlType);
+                    }
+                } else if (logical instanceof XMLType && isMany) {
+                    ((XMLType)logical).setMany(true);
                 }
                 return true;
             }
diff --git a/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDOTypeHelper.java b/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDOTypeHelper.java
index e3ec6dc..6f5443f 100644
--- a/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDOTypeHelper.java
+++ b/modules/databinding-sdo/src/main/java/org/apache/tuscany/sca/databinding/sdo/SDOTypeHelper.java
@@ -70,16 +70,16 @@
         QName xmlType = JavaXMLMapper.getXMLType(javaType);
         if (xmlType != null) {
             return new TypeInfo(xmlType, true, null);
-        } else if (javaType == commonj.sdo.DataObject.class) {
-            return new TypeInfo(SimpleTypeMapperImpl.XSD_ANYTYPE, true, null);
         } else {
             // introspect(javaType, xsdTypesMap, typesMap);
             if (logical instanceof XMLType) {
                 xmlType = ((XMLType)logical).getTypeName();
             }
             if (xmlType == null) {
-                xmlType =
-                    new QName(JavaXMLMapper.getNamespace(javaType), Introspector.decapitalize(javaType.getSimpleName()));
+                // TUSCANY-3298: dynamic SDO or collection of dynamic SDO
+                return new TypeInfo(SimpleTypeMapperImpl.XSD_ANYTYPE, true, null);
+                //xmlType =
+                //    new QName(JavaXMLMapper.getNamespace(javaType), Introspector.decapitalize(javaType.getSimpleName()));
             }
             return new TypeInfo(xmlType, false, null);
         }