I wish I could offer some great help here, but I too suffer from the same malady and from what I have read at the Mozilla forums (and elsewhere) there isn't a fix/patch/whatever for it.
I'm guessing the folks at Logitech (my trackball's mfg) didn't bother to think about non-IE using web surfers when they put together the software for their otherwise wonderful trackball.
However, I haven't checked at the Mozilla website's forum area in a while so you may wish to try yourself and see if you can find anything.
I just got a marble mouse and I can't use the scroll buttons to up or down on the page. I have firefox 1.5 and I don't know how to customize for this problem. Is there a way to fix this Thanks