Response is lost from SwitchYard application in FSW 6

Issue

• I am having problems trying to create a SwitchYard application with the caller and receiver outside SwitchYard.
• Call is executed correctly, but response is lost in return.
• My switchyard.xml is as follows:

<sy:switchyard ...>
  <sca:composite name="sample" targetNamespace="urn:com.example.switchyard:sample:1.0">
    <sca:service name="SampleService" promote="SampleComponent/SampleService">
      <sy:interface.esb inputType="java:java.lang.String"></sy:interface>
      ...
    </sca:service>
    <sca:component name="SampleComponent">
      ...
    </sca:component>
    ...