<Fn><F2> and <Fn><Fn><F3> without effect

[farinet at arcor.de]

Ok, my Samsung is a problematic device for linux but BrightnessUp and
BrightnessDown should work ;)

I checked with xev and the keys show correctly F86brightnessup -down.
Now, i thought that would be automatically related to xbrightness -inc
respectively -dec. But obviously it isn't.

Btw, i've the same problem with volume keys.

Where and how can i set this in lubuntu? Vaguely i remember the keyboard
settings of gnome 2 ...

TIA.