SB Audigy ZS 2 and 5.1 Question

I'm having a tough time getting this to work. I can get my receiver to recognize stereo using one side of a 3.5mm minijack to stereo RCA cable. I've got it running from the digital out to the coaxial input on the back of the receiver. I'm running ffdshow and zoomplayer. What am I missing? I think it has something to do with the passthrough side of the applications. zoomplayer, ffdshow, creative. They dont' all seem to be collaborating very well.

If you have this card and can hear 5.1 from your receiver tell me how you did it and what you're playing back with. Thanks!

That I think is the whole of my issue. I'm pretty sure that in ffdshow I'm supposed to find the AC3 codec and change it to SPDIF. That is supposedly supposed to pass through the AC3 out the 'digital out' of the Audigy ZS2. But I think the creative drivers are also getting in the way and creative's site talks about disabling dts so that it completely passes through to the receiver to be decoded. In addition to DVD I have other files that have AC3 and DTS encoded as well.