Sending Attachments using WSIF

Hi

I have question is it possible using WSIF to send attachments without wsdl defintion saying about.I am sending the attachment

as follows

final DataHandler dh = new DataHandler( "sample content ","text/plain" );

final WSIFServiceFactory factory = WSIFServiceFactory.newInstance();

final WSIFService service = factory.getService( " http://my.wsdl ",null, null, null, null );

final WSIFOperation op = service.getPort().createOperation( "testAttachment" );

final WSIFMessage in = op.createInputMessage();

in.setObjectPart( "param1","myparam");

in.setObjectPart( "attach", dh );

op.executeInputOnlyOperation( in );

Service defintion looks like

testAttachment ( String param1)

The problem is when i try to retrieve the attachment from axis message i am not recieving anything.Obviously i am doing something

wrong.Please guide me over this problem

Thanks

Amey