Playstation 2 and Sound Blaster Audigy - Surround?

Hey everyone I have a question I'm hoping you can help me with. I have a
Playstation 2 console, and an internal Audigy PCI in my desktop. The Audigy
is just the card, no drive kit or anything else. I'm also using Creative
5.1 speakers for sound. Is there any way at all to hook up the PS2 to the
Audigy and have it use those speakers for surround sound? Even if its just
Pro Logic or something like that. I know I can't get DTS but what about Pro
Logic? I've tried splitting the 2 RCA red/white cables into 1 1/8" jack and
plugged it into the line in port on the Audigy. The only thing is that
sound only plays from the 4 speakers, not the centre one, and I don't think
it's in surround, I'm pretty sure each speaker is playing the same thing.
Is this at all possible or is there some sort of cable I can get? Or should
I just trade in the old Audigy for an Extigy to do this. Thanks a lot.

Lee