adjusting screen brightness

[Alimin Bijosono Oei]

Hi,

I own a compaq presario 1500ap laptop and running FC1.
Is it possible to get the keyboard keys for adjusting screen brightness 
work? I managed to get other special keys work. Can the screen 
brightness itself be adjusted? I am not familiar with the underlying 
technical stuffs, is this something to do with X or anything else? 
Thanks for any help provided.

Alimin