twistdown code

From
http://wilson.ai.mit.edu/cl-http/twistdown-tree/twistdown.html
"If you think of any cool enhancements, please let us know on
[email protected]. For applet documentation see
http://mit.edu/cvince/www/java/kbcw/hdir/."

Well, I thought of a cool enhancement, but I'm not sure about how to
implement it.  In the example code, when a terminal node is clicked, java
loads a specified url (by default http:*cl-http-home-page-url-string*). If
there were a way to pass the value of the node back to the Lisp
environment, that would be great.  Does someone know how to do this?

Thanks,

Ben