Script Callback when 'onWorldLimit' occurs?

Does anyone know if it is possible to have a script callback occur when an objects 'onWorldLimit' is called? It appears to only accept 'null,bounce,kill' and a few other strings, but nothing that would allow one to place their own script callback.

The bottom of this post appears to mention that it may be possible, however I have never gotten the posted code to function:
http://www.garagegames.com/mg/forums/result.thread.php?qt=31357

Any help is appriciated,
-Dave C.