Asus M2A-VM HDMI Does not work with External Surround Sound System

Ok so i have built a HTPC.
# New Mid Tower Case with 550Watt Power Supply
# ASUS M2A-VM HDMI Motherboard (microATX)
# -AMD 690G Chipset
# -Onboard HDMI/DVI output at 1080p (Daughter card that came with the motherboard.)
# AMD Athlon 64 X2 - 3.2 Ghz Processor
# 3GB DDR2 RAM (upgradeable to 8GB w/64bit processor and OS)
# 300GB SATA 7200RPM Hard Drive
# -Digital 7.1 Surround Audio

I also have a HDTV 46in SONY BRAVIA KDL-46S4100 and a DVD Home Theater System SONY DAV-HDX576WF. Currently, all devices are plugged digitally into the TV (via HDMI or Component Cable), and out to the Surround Mixer via OPTICAL.

For PC Audio, I have HDMI enabled in the BIOS, and the sound is working through the TV ONLY. Sound for some reason, will not pass to the Surround Mixer.

I am running the REALTEK 5.10.0.5404 Driver, which brings up an ASUS control panel to configure various different audio settings, inputs and outputs. Mine is set to REALTEK HDA HDMI OUT, which is the HDMI cable on the rear of the PC, running into my HDTV.

The guy at Tiger Direct said this mother board has been popular in the past 6 months, and said "customers have told me "don't use the realtek driver - that usually fixes it." Ok - well, i don't know what else to try. Has anyone else had the same issue and perhaps found a solution?

Thanks!