<?xml version='1.0' ?>
<env:Envelope xmlns:env="http://www.w3.org/2003/05/soap-envelope"> 
  <env:Header>
    <test:requiredHeader xmlns:test="http://example.org/ts-tests"
          env:mustUnderstand="true">
      foo
    </test:requiredHeader>
  </env:Header>
  <env:Body>
    <test:echoHeader xmlns:test="http://example.org/ts-tests">
    </test:echoHeader>
  </env:Body>
</env:Envelope>