These kind of questions are best answered on the Metro forum. Henceforth please post webservices questions on Metro forum for quick response.
You seem to have an STS and it looks like the STS needs the username/password for authentication. However the wsit-client.xml that you have setup has client side configuration only for the WebService and not the STS.
Check the create-client section of the following post :
http://blogs.sun.com/shyamrao/entry/simple_way_to_develop_ws
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