How to use getWorkspaceTreeAsXML ?

I am going through the documentation, forums and source code, but I can't seem to find a way to make getWorkspaceTreeAsXML in a JSP. A sample which calls it and just 'dumps' result to screen would be good enough to get me going. I am working on a dynamic horizontal dropdown menu which would traverse a branch of the tree to build the menu and sub-menus. I have the 'static' version working, just need to 'read/walk' the subtree on the fly.

I'll post the resulting code in Vibe Cool Solution blog.