Debian Recognizes SB Live but only 2 spkrs work
 

Hello. I have a SB Live 5.1 sc installed, recognized by Debian, but cant'g get my 5.1 soundsys to work. I'm using OSS and Kmix. I get good sound from front L and R, and almost nothing from rear L and R, and nothing from the center speaker or the SW. Thing is when I mute front L and R, rear L and R keep on working, but as before, almost inaudible. WHat can I do to make all speakers work? or to for example set up EAX? Is there a way?
Regards,
Mariano
(using Debian 2.4.31 kernel)