Audigy 2 Platinum Pro - XBOX

I recently purchased a creative audigy 2 zs platinum pro. I wanted to use it to hook my xbox up to so I could get surround sound when I play games and watch DVD's. However, when I plug the optical cable from the xbox audio output into the front optical in port in the audigy 2 I get a split second sound delay. So, when I'm watching a DVD with surround sound enabled, people's lips don't match up with their words perfectly. It is REALLY annoying. I believe the problem is that the 5.1 signal is getting decoded twice; once by the xbox and then again by the soundcard. Unfortunately, I can't figure out how to turn the soundcard decoder off and still get a signal. When I turn off the sound card decoder, the sound card stops transmitting a signal alltogether. When I set the sound card to "spdif bypass" or "default" I get no soundwhatsover. However, if I leave the soundcard set to "default" and set the xbox to stereo sound, I recieve a perfectly synched stereo signal. I wish there was a way to just get the audigy 2 to play the 5.1 signal it was recieving and not decode it. Please help!