What's the problem with my sound system?

I have the oddest problem w/ my Soundblaster Audigy MP3+ and (has anyone heard of these besides me?) Yamaha TSS-1 5.1 speakers. (<A HREF="http://yamaha.com/cgi-win/webcgi.exe/DsplyModel/?gSPK00..." target="_new">Click here for stats on TSS-1</A>) I hate it when I have problems like this where it could be one or the other or both and I'm waiting 20 minutes lisining to bad oldies and nobody knows anything about the other on the customer support, IT DRIVES ME CRAZY!!! Anyway, I've got the obscure speakers, which should have built-in Dolby Digital and DTS, but I'm only getting Prologic. Also, in my reaserch on this, I've been reading about how Creative's digital output can put all 6 channels on one cable, and I frankly don't think I have the right cable. When I test the speakers from Creative's Sound Mixer, I only hear front left and right, with the right a little staticy. The ironic thing is, as of now, it works wonderfully, I get incredable sound out of all 5.1 speakers, but I wonder if maybe I'm not getting everything I can out of this setup. Anyone have anything that could possibly help me?