asus p5e surround sound problems

hello. i recently purchased an Asus P5E motherboard. It has the Supreme-FXII pcie sound card which the manual says is an ADI AD1988B. I've been using it with my regular 5.1 speakers using the colored output jacks on the card, but I want to use the optical or coaxial output to my receiver so i can use my better sound. i hooked it all up, made sure my receiver is hooked up all right, test tones come through fine, and my stand-alone dvd player puts out sound through it fine, but when i use either digital output from my motherboard to it, I get only stereo signals. No surround. I've tried the optical output and the coaxial output, and i've tried all 3 inputs on the back of my receiver, plus two different cables of each type, so it is not that. I'm dual booting XP x64 and Vista Ultimate x64. In vista when i load up SoundMAX Blackhawk, and switch to SPDIF and click the surround settings, it lists only Stereo and Headphones as my options. I click More Settings and go to my speaker trim options, and everythihng but front left and front right are greyed out. Port settings shows it as using my Rear Panel Digital optical port. I have my SPDIF interface as my default playback interface. I have tried AudioESP both on and off, and the "disable digital output" is unchecked. It simply does not ouput surround.
My XP is slightly different. same output problems. No surround with digital, but setting up which speakers i'm using is not automatic as it is in vista. I have set it to 5.1 surround sound speakers (also tried 7.1 and quadraphonic), and again all my settings show exactly what they should. When i do the sound test from SoundMAX in XP, and have the sound go around the circle, it cuts out just as it gets to the rear speakers and comes in again when it gets back around to the front. My Center speaker is also out.
Does anyone have any idea what my problem is? Perhaps its a known problem, or maybe i'm somehow missing something? I believe i have the most current drivers in both OS's but I will of course double check all that. I also have 32-bit XP MCE installed but i have not tried that as i havn't ever actually needed it (i figured 64 bit would be incompatible with everything but actually haven't had issues lol).

Thanks in advance!

DVo

Arg, I posted a reply but apparently it didn't stick. So here it goes again.

5.1 encoding over optical is usually done in hardware using some fancy audio processors. However, most mobo's don't have them (including the p5e), so what you will get is 2 channel output until you use a media source that has already-encoded 5.1 audio, like a DVD/Blu-Ray, that can just be sent over the channel without any processor overhead. I would try playing a DVD with some 5.1 dolby digital audio, you should see/hear that the other 4 channels will start working as they should.

There might be some software out there that uses the processor to do the encoding, but I don't know any off-hand.

Hope that helps,
-gripen40k

Hello guys! I have the P5E motherboard and for the time being it seems that the 5.1 surround doesn't work. I've been using my Logitech z-5300 Z 5.1 speakers using the jacks on the card with no surround effect! Does you card play correctly using the coloured jacks? If yes could you please advice what should I do?

Thank you in advance guys!