Using MORE than one Sound card

I've installed Knoppix v5.1 to my HD as a Beginner-type installation, after ironing out several problems, i'm facing another one. I happen to have THREE sound cards in my PC: Two PCI, & one on-board (motherboard) sound. Sound works ONLY through the on-board sound. The other two, Audigy 2 ZS & Live! 7.1 do NOT work. I'm hoping the problem is simply a matter of choosing either soundcard as the default output, like you can in Windows. In Windows, i would do this by right-clicking the mixer icon on the taskbar, choose 'Adjust Audio Properties', and in the 'Audio' tab select a soundcard from the 'Default device' from the dialog box. Is there a similiar feature in Knoppix? Is it more involved/complicated then this? I'm pretty sure ALL three sound cards are detected with drivers working properly, because Kmix has a separate mixer for three devices: HDA Intel, CA0106 (Live! 7.1), & Audigy 2 ZS. Also, KinfoCenter lists the three soundcards under Sound. I'm still a relative newbie to Linux, some help on what to do next would be very helpful.

Thanks in advance.

Hello....anyone? Please? I feel neglected here, and i'm on the verge of heading back to Windows.