I am having problems enabling the screen brightness keys in Ubuntu 12.04 LTS. I was able to find a instructions to enable the function keys for the backlit keyboard but I can not find instructions for the fn keys that control the screen brightness; and yes, I do know how to adjust the brightness from the power menu.
I ad the same problem. The key is to hold down the "fn" button on the bottom left of the keyboard while holding the fkey you want to press. give it a few seconds and it should pop up on your top right corner of the monitor. It's kind of finicky but it works. (I run ubuntu 13.04)