This is an example wsdl

<portType name="BS_FooService">
  <operation name="callService">
     <input message="RequestMessage"/>
     <output message="OutputMessage"/>
     <fault name="exception" element="FaultMessage"/>
  </opertaion>
</portType>

<message name="RequestMessage">
  <part name="metadata" element="metaElement"/>
  <part name="payload" element="inputElement"/>
</message>

<message name="ResponseMessage">
  <part name="metadata" element="metaElement"/>
  <part name="payload" element="outputElement"/>
</message>