Utilize side buttons on g5 for back and forward

Hey guys, I have a Logitech G5 laser mouse (the blue crackle one w/ two buttons on the side) and i was wondering if there is a way to set the two side buttons to go forward and backward when I'm in a web browser. I know they work because i can map them to all sorts of stuff such as expose and dashboard but that's not what i really want them to do. I've also heard a lot of people say that side scrolling works out of the box for them. For me it does not. Maybe they have the older G5 (carbon look sort of w/ a single side button). Is there a way, that maybe i don't see, to make that work?

Thanks,

Lucius