Need Help Deserializing Custom Classes

[Davis, Jonathan]

Hello, having trouble getting the server to deserialize a custom class:
this error message is returned: 

faultString: org.xml.sax.SAXException: Deserializing parameter 'arg0':
could not find deserializer for type AuthenticateUserRequest

The client can deserialize it (after I added the lines to register the
type mapping) but the server is still unhappy. 

Client code: 

        Call client = new Call(endpoint);
        QName qn = new QName("AuthenticateUserRequest");
        client.registerTypeMapping(AuthenticateUserRequest.class, qn, 
                                   new
org.apache.axis.encoding.ser.BeanSerializerFactory(AuthenticateUserReque
st.class,qn), 
                                   new
org.apache.axis.encoding.ser.BeanDeserializerFactory(AuthenticateUserReq
uest.class,qn));                                   
        client.addParameter( "arg0", qn, ParameterMode.IN );
        AuthenticateUserRequest request = new AuthenticateUserRequest();
       String ret = (String)client.invoke(new Object[] { request });

I'm not sure about the addParamater line, is that supposed to add an
additional parameter that tells the server about the TypeMapping? 

Thanks in advance