A old problem once again
The multimedia keys on my keyboard are not recognized during install
So a search through this forum for xbindkeys as i remember it was called gave me the info in a number of posts howto use it. nearly 6 years old some.
Download from XBindKeys
Extract with ARK
In the map containing the outcome of ark
then make and su + passwrd make install
In the readme file is the dokumentation.
Hope it will ring a bell as you see your keyboard.