Don't dispair. A soundblaster Live 5.1 card can work properly under Linux, I am fairly certain of that.
I am using a Soundblaster Live 5.1 card aswell, and for stereo (2 speaker) system it is perfect for me. I am using OSS as my sound driver though. ( I couldnt get ALSA to work when I tried it, OSS works for me, so I left it at that).
For the problem you have, I would first check the sound volume control mixer panel if your using Gnome desktop. You will find it if you right click the little speaker icon in the right hand end of your bottom Gnome panel. When you right click the icon, a menu will appear, choose "Open Volume Control" from the menu and check that your volume levels, maybe you have one of them turned down?
CTRL+O will also open the Volume Control.
As far as getting the full 5.1 speaker system to work, I would not know, hopefully someone else can advise on that.