How do I make firefox or any other xulrunner based application float above all other windows on Mac 10.6 and up?

afloat is very useful to keep the window above all windows on Mac, but only cocoa based applications. Is there a way that I can implement this functionality for other applications programmatically. firefox example

I don't want to use afloat, but I would like to know how to code this function on Mac.

Thank you so much!