[Rob00GT]

I just built a new Home Theater PC using the following components.

Asus M3A78-EMH HDMI motherboard (AMD 780G chipset)
AMD Athlon64 X2 5000+ Black Edition
XBOX360 external HD-DVD player
Windows XP Pro SP3 (with all patches and updates)

Playback software:
Cyberlink PowerDVD Ultra 7.3
Nero Showtime 3.10.1.0 (part of Nero 7 Ultra Edition)

So I've got it all put together and it works great. I'm using the HDMI connector for both picture and sound. The HDMI cable is connected first to my Sony STR-DG910 home theater receiver which pulls out the audio portion then passes the video to my Samsung DLP HDTV. I get a great picture in 1920x1080 but the sound through my receiver only comes out in stereo. I've tried adjusting every setting I can find but can only get stereo sound. The same for both Cyberlink and Nero playback software so it must be a Windows problem, right?

How do I get dolby digital output? I've got everything setup for 5.1 goodness but no joy.