getLogicalPort() returning NULL

Hi Experts,

I created a deployable proxy and I am able to lookup the service. But when it comes to call the method getLogicalPort, it returns NULL and I just can't figure out why. Calling getLogicalPort using a standalone proxy works fine. Is there anything wrong with my coding?

InitialContext ctx = new InitialContext();
IndexManagementWS service = (IndexManagementWS) ctx.lookup(mWebserviceKey);
IndexManagementWSViDocument vi = (IndexManagementWSViDocument) service.getLogicalPort();

Or am I missing anything else?

Thanks & Regards

Georg