Actually, probably none. He sounds to have sound working fine, but is now in the process of getting it fine tuned.
I believe that they do use ALSA in RH8, so you might wanna see if there is something along those lines that might point you towards a better answer.
With mine, I have 4 speakers too. I used to run them through some crappy basic card. So I only had the 2 speakers working. Then I got me SB Live and as soon as I plugged in the cable to the black plug on the card, the rear speakers started working. I haven't had to edit any files at all.
But I am not running ALSA, although even when I was (in Mandy) it still worked.
Check alsamixer, see if that gives you options for the things you are looking for.
Good Luck
Cool