if you installed the drivers correctly, the old dimmer buttons (f14 and f15) should work. if not, there should be a lil LCD icon in the tray. click it and drag it to your appropriate settings.
right after I posted this I seen the little lcd in the tray. Problem is... everytime I click on it and drag it down it reboots my machine. I'll give the keys a try and see how it works from there. Did anyone else have this problem and if so.. whats the fix?