I have Knoppix, I installed all the ALSA packages and configured them by what ALSA said, that and installing them through apt-get, asks you questions about your sound card. To the point, I'm using gamix for my ALSA mixer, I also have a 6 channel speaker system.

How I got 5.1 working on my system, I either use Xine or Kaffeine for a mediaplayer, Using defaults in the prefferances, except in audio tab, I have it on Surround 5.1. Now on gamix I have to have volumes turn alll the way up on Master Playback, Surround Playback, Center, LFE. On the IEC958 spot I have output checked and the bar is all the way to the right. SPDIF source is on Digital, I don't have Duplicate Front checked. I do have External Amplifier checked, finally I have Audio Data Type on AC3. After gamix is configured that way I then adjust the volumes on my speakers to control rear fading and front volumes levels and over all levels.

Well I hope this helped some people out, took me a while to figure it out myself.