how to output via SPDIF to AV receiver to get 5.1 sound???

[aussiemac]

I have finally got my big screen and htpc setup.
Now i have to fine tune it!
hopefully someone can help..with suggestions or settings??

I have an optical connection between my HTPC
and an A/V receiver(with Dolby digital and DTS decoding capability)
The HTPC has an onboard sound chipset...C-Media 9880L
with driver version 5.12.1.8.

I can get 5.1 and DTS output playing a DVD thru the HTPC.

I can only get Dolby digital 2ch playing a DVD on the hard drive
using media player classic 6.4.9.0.
I can only also get Dolby digital 2ch from Xvid movies (which have attached 5.1 DD sound)
using Media player classic 6.4.9.0.

Is there anyway of changing decoding or filter settings to get this C-Media card to output
the raw stream to the AV receiver and not impose its two channel DD setting
on the Xvids and DVDs on hard drive??

I have PowerDVD 6 and WinDVD and AC3 filter installed as well.

In powerDVD 6(with DD5.1 and DTS) I have SPDIF out ticked ..
and in AC3 filter SPDIF output set .

Do I have to set something in Win XP registry to force the Cmedia Sound
card/driver to output
5.1 sound ...ie all six channels?

Hopefully someone can point me in right direction..TIA

[Baldrick]

please don't cross post. one topic is enough.
https://forum.videohelp.com/viewtopic.php?t=310667&highlight=