I cant change it using the menus. I click on driver press the right arrow, the other driver appears, i click apply and on ok it still shows the old one.

Editing the config file worked.

I also noticed this today, as i switched my driver from OSS to ALSA i tried doing it in the menu, ALSA was there as a chioce, but no matter what i clicked, (Accept, OK) the driver changes back, you can reopen the Audio Menu to verify this, but like AgY states, changing it manually to ALSA driver worked..... Have not before today tried changing the driver under linux, so i do not know if this is a recent issue, but only the ALSA driver properly supports my 5.1 output ;)

Look in the Linux forum:
http://www.vendetta-online.com/x/msgboard/6/5923

Yep, Linux is the only platform with multiple sound drivers so that code has been a stub for a long time. Someone will fix this eventually. The default behavior (in the absence of a configuration file) is to try to use ALSA and fall back to OSS, so it's not super urgent that we fix this IMO. I could also combine them into a single driver and just have an option or something if we can't get sound driver switching to work..