invoke returns null and the response is valid

[Matias Woloski]

I have a message style webservice on Axis 1.1. I make this request using the
Axis api:

org.w3c.dom.Element elem = Convert.toDomElement( SUBMIT_QUERY_XML_MESSAGE
);
org.w3c.dom.Element[] input = new org.w3c.dom.Element[] { elem };
Object response = call.invoke( input );
Assert.assertNotNull( response );       

Using TCPmon I see the request soap envelope

 <soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/";
xmlns:xsd="http://www.w3.org/2001/XMLSchema";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";> 
      <soapenv:Body>  
         <submitQuery
soapenv:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/";>   
            <arg0 xsi:type="ns1:Element"
xmlns:ns1="http://xml.apache.org/xml-soap";>    
               <message>     
                  <usernameToken>            
                     <user>garrahan</user>           
                     <password>1234</password>    
                  </usernameToken>    
                  <query>           
                     <SubmitQueryRequest
iD="E8E0D31E-49C4-A948-8615-9A076AF6415C" timeOut="100">                    
                        <request>                           
                           <dni>20</dni>                
                        </request>      
                     </SubmitQueryRequest>   
                  </query>  
               </message> 
            </arg0>
         </submitQuery>
      </soapenv:Body>
   </soapenv:Envelope>

And the response as follows:

<soapenv:Envelope xmlns:soapenv="http://schemas.xmlsoap.org/soap/envelope/";
xmlns:xsd="http://www.w3.org/2001/XMLSchema";
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance";> 
      <soapenv:Body>
         <SubmitQueryResponse iD="E8E0D31E-49C4-A948-8615-9A076AF6415C"
start="2004-08-11 17:01:33.171" taskCount="2"/> 
      </soapenv:Body>
   </soapenv:Envelope>

However, the response is always null.

Any ideas?

Thanks,
Matias