servlet delegation problem.(stupid me can't get 15 lines of code right)

[ro...@zzict.nl]

Yo
dudes,
it's late, and I have been looking at this for too long now:
The idea was simple: 
store all JSP pages that need authentication in a NEEDSAUTHENTICATION
subdirectory and put a servlet in front of it that checks wether 
the session was authenticated, and delegate to a logon page if not,
and delegate to the normal JSP handler if it was.

In theory this is 15 lines of code maximum.
But I can't get It to work:
If or the request get's delegated to this servlet again, by the
Dispatcher, or the servlet engine goes and looks for the pages in
the wrong directory (forward eats a part of the path.)
 

The servlet 
looks like this:

public class BasicAuthenticationServlet extends HttpServlet {

    public void doGet (HttpServletRequest request,
                       HttpServletResponse response) {

        try {
            HttpSession session=request.getSession();
            String isAuthenticated= (String)
                   session.getAttribute("isAuthenticated
");
            if(!"true".equals(isAuthenticated)){
            getServletConfig().getServletContext().getRequestDispatcher("/logon.jsp").forward(request, response);
            }else{
                String uri=request.getRequestURI();
                RequestDispatcher dispatcher=

getServletConfig().getServletContext().getNamedDispatcher("jsp")
;
                dispatcher.include(request, response);

                 }
        } catch (Exception ex) {
            ex.printStackTrace ();
        }
    }
}


Help is appreciated.

Sloot.