This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Not sure if this answers your question, but if you use Axis, you can get at the underlying HttpServletRequest like this.
Or are you talking about using certificates in the context of WS-Security? Then you'd be looking at using a package like WSS4J, and the outline of what to do would be something like this. [ March 21, 2006: Message edited by: Ulf Dittmer ]