Surround Sound Support?

Greetings,

I am currently having somewhat of an annoying issue with this operating system. Before, I used to run Windows XP 64bit edtion, everything on there worked fine (including the 5.1 HD audio system I have). Now in this os, I only get sound out of 2 speakers (L + R). On top of that everything seems to be in lower volume, but, I'm assuming that's because there's only sound coming out of two speakers (I hope). I know it's not my hardware b/c it worked fine before in the previous os that I have mentioned, I also have a laptop that I used and it worked fine on that too, Vista is the only one giving me the problem.

I have the latest soundcard drivers installed from Auzentech's website and it's enabled to go Dolby Digital Live (DDL). I did disable onboard audio in the bios menu as well.

Here's what I have:
(Auzentech X-Meridian Soundcard: Optic cable to Panasonic XR-55 receiver)
(Speakers: Onix X-Series 5.1)
-Other info:
Intel C2Quad Q6600
Evga 680i Motherboard
Evga 8800GTS (640)
1x Raptor X150 HD
1x WD Storage 250G HD
620W Corsair Modular PSU
4GB of Patriot Extreme Memory

Is there a way to set up the devices in some type of menu? Or do I have to roll back to XP?

I`ve found this information but I don't think it`ll help much:

Audio output and Speaker setup (Vista)

for DVD settings and audio such as AC3 Dolby Digital 5.1 surround
Open the AC3filter configuration shortcut, in the upper left you will see, Output format -
the default setting is : AS IS (no change) ..... you may set it as you wish.

All other audio playback
Open the Audio decoder configuration shortcut, scroll the left window down to 'Mixer',
place a check in the 'Mixer' box, and in the righthand window select you speaker setup in the drop down list
Then check the box for LFE if you have a subwoofer attached.

To use SPDIF output
Go into Vista's Control Panel and navigate Sound/SPDIF/Properties/Advanced/Exclusive Mode
(depending on your sound device, the above path may be a bit different but similar)
Then CHECK the box [x] for the following 2 items
'allow applications to take exclusive control of this device'
'give exclusive mode applications priority'

If you are experiencing choppy or stuttering sound
Go into Vista's Control Panel and open the Sound applet
Select your output device in the list that appears
NOTE: the default output device is commonly labeled Speakers
Right click on the device and from the context menu click Properties.
Click on the Enhancements TAB.
Then CHECK the box [x] for Disable all enhancements.