WSS4J in WebSphere 5.1.2??????

I have a simple Web Service in WebSphere which is working fine. Now I want to secure that service using wss4j UserName Token. I have included the wss4j jar. Then what is the code and way to go ahead to secure the service using the wss4j apis? I have been trying this for a lot many days.But still I

How do I implement wss4j in Websphere 5.1.2?

I have a simple web service in WSAD. I have also added the wss4j.jar file.Thus I will be able to access the classes. But how do I secure the web service using UserName Token using the wss4j apis in websphere? Please let me know. I am really stuck on that. _