I have an UL80VT, which is almost the same notebook.
Executing the following command from a terminal changes the screen brightness, at least when the intel card is running (needs root privileges):
setpci -s 00:02.0 F4.B=XX
where XX is an hexadecimal number from 00 (LCD off) to FF (max brightness).
I found this tip in a guide for ubuntu (which I can't find anymore) that also provided a customized script to execute that command automatically when using Fn keys. That didn't work on F14 and I never tried in F15.
Does anyone know how to tell the gnome/KDE power manager (or whatever backend is actually responsible) to use that command instead of whatever they normally use?