Wanted to replace old keyboard with the new Apple wireless keyboard on my Mac OS X 10.5.8... Got through the process of pairing OK, changed keyboard shortcuts key for brightness to F1 and F2 OK, but sound volume and mute keys (F11, F12 and F10) do not wo

Wanted to replace old keyboard with the new Apple wireless keyboard on my Mac OS X 10.5.8... Got through the process of pairing OK, changed keyboard shortcuts key for brightness to F1 and F2 OK, but sound volume and mute keys (F11, F12 and F10) do not work and in the list of "Keyboards shortcuts" there is no such thing as volume decrease/increas/mute... How can I make these volume keyboard keys work.

(My old wireless keyboard that came with this copmuter is similar to the new one and worked just fine with all keys, till my cat nocked glass with water on it, then, I used old USB keyboard and it worked just fine with all keys, but this NEW wireless does not want to control sound volume...)