SwitchYard soap web service always returns null

Question

I'm calling a switchyard web service using a simple java program with jax-ws. Our production server is a jboss eap 6.1 with switchyard 1.1 and i'm making tests with wildfly 10.1.0 and switchyard 2.1. In both environments the situation is the same, when i call the web service the return is always null despite the server response (by tracing) looks good.

Example of a request/response:

REQUEST:

<?xml version="1.0" ?>
<S:Envelope xmlns:S="http://schemas.xmlsoap.org/soap/envelope/">
  <S:Body>
  <ns3:identifyUser xmlns:ns3="urn:pt.ipc.pio:pio-organizationservices:1.0" xmlns:ns2="urn:pt.ipc.pio.model.organization:1.0">
  <identifyUserInput>
  <userName>****************</userName>
  </identifyUserInput>
  </ns3:identifyUser>
  </S:Body>
</S:Envelope>

RESPONSE:

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">
  <SOAP-ENV:Header xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/"/>
  <soap:Body>
  <identifyUserResponse xmlns="urn:pt.ipc.pio:pio-organizationservices:1.0">
  <ns2:userIdentity xmlns:ns2="urn:pt.ipc.pio.model.organization:1.0">
  <uniqueId>**********</uniqueId>
  <personalData>
  <nif>**********</nif>
  <name>**********************</name>
  <gender>*</gender>
  <identification>********</identification>
  </personalData>
  <ous>
  <ou>****</ou>
  <numSGA>********</numSGA>
  <numInt>*****</numInt>
  <role>***************************************************************</role>
  <type>*****</type>
  <emailAlt>*******************</emailAlt>
  <active>****</active>
  <admissionDate>**********************</admissionDate>
  </ous>
  <preferedOU>
  <ou>****</ou>
  <numSGA>********</numSGA>
  <numInt>*****</numInt>
  <role>***************************************************************</role>
  <type>*****</type>
  <emailAlt>*******************</emailAlt>
  <active>****</active>
  <admissionDate>**********************</admissionDate>
  </preferedOU>
  </ns2:userIdentity>
  </identifyUserResponse>
  </soap:Body>
</soap:Envelope>

I made some tests with a http server hardcoding the response and notice that if i change the xml from

  <identifyUserResponse xmlns="urn:pt.ipc.pio:pio-organizationservices:1.0">

to

  <ns:identifyUserResponse xmlns:ns="urn:pt.ipc.pio:pio-organizationservices:1.0">

(adding the namespace identifier) the java client starts to work.

Tested with jax-ws ri, metro and cxf and the result is always the same.