CL Audigy + Inspire = DTS?

[Munkee]

I hope somebody here knows how to answer this. I've had an Audigy for a while but I just now got my CL Inspire 5.1 5700. I decided to test it out after setting it up and heres the problem: I set the Audigy to digital output only (digital DIN connector), 5.1 speaker setup, and disabled the Audigy's onboard decoding to use the external decoder. I run a DVD (in WinDVD or PowerDVD w/ audio set to S/PDIF) in Dolby Digital it runs fine. The indicator on the decoder lights up telling me its decoding AC-3. But if I run the DVD in DTS which the external decoder is supposed to handle,(same settings: S/PDIF, digital output, onboard decoding disabled) the DTS indicator on the decoder will blink once, then shutoff. I'll get no sound and the movie runs REAL choppy. If I switch it back to dolby on the root menu it runs fine. Am I doing something wrong? Somebody help please!