Audio Problems in CSS and HL2

[Dani]

Can't use the setting 5.1 speaker system. I have a Creative Inspire 5300, 5.1 and a SB Live sound card. The only setting I can use to get sound is 2.1 speakers. Then only 2 speakers is up and running. I have only Win XP drivers for my sound card so this might cause some problems. But games, movies, music have worked perfectly so far. How can I fix this?

thanks!

/dani