How to add "sap.com/tc~kmc~bc.uwl~api " reference to a web service in NWDS.

Hi ,

I have a web service created in NWDS for "UWL item count & display". I have the below code in it for

// retrieve UWL service

IUWLService uwlService = (IUWLService) ctx.lookup("/broker/services/" + IUWLService.ALIAS_KEY);

When code was checked line by line , I find the error happening due to the above line of code. And the error is as follows :

An error has occurred. Maybe the request is not accepted by the server:

com/sap/netweaver/bc/uwl/IUWLService

What is this error due to ?

If it is due to the reference "sap.com/tc_kmcbc.uwl~api " not being added , then where do I add this reference in web service perspective. ?

Suggestions invited.