mustella/tests/mobile/components/ButtonBar/swfs/Assets/MyBBSkin.mxml

<?xml version="1.0" encoding="utf-8"?>
<!-- http://blog.flexexamples.com/2009/07/28/displaying-icons-in-a-spark-buttonbar-control-in-flex-4/ -->
<s:Skin name="MyBBSkin"
        xmlns:fx="http://ns.adobe.com/mxml/2009"
        xmlns:s="library://ns.adobe.com/flex/spark"
        alpha.disabled="0.5">
    <!-- states -->
    <s:states>
        <s:State name="normal" />
        <s:State name="disabled" />
    </s:states>

    <fx:Metadata>
    <![CDATA[
        [HostComponent("spark.components.ButtonBar")]
    ]]>
    </fx:Metadata>

    <fx:Declarations>
		<fx:Component id="firstButton">
			<s:ButtonBarButton skinClass="Assets.MyBBButtonSkinFirst" />
		</fx:Component>
		<fx:Component id="lastButton">
			<s:ButtonBarButton skinClass="Assets.MyBBButtonSkinLast" />
		</fx:Component>
        <fx:Component id="middleButton">
            <s:ButtonBarButton skinClass="Assets.MyBBButtonSkinMiddle" />
        </fx:Component>
    </fx:Declarations>

    <s:DataGroup id="dataGroup" width="100%" height="100%">
        <s:layout>
            <s:ButtonBarHorizontalLayout gap="-1"/>
        </s:layout>
    </s:DataGroup>

</s:Skin>