Valve (CS/HL2) surround sound

Does anyone have experience with ATI Radeon HD cards and Valve games? I'm trying to find the solution to getting surround sound from Counter-Strike and Half-Life games but am only getting 2 channel. I know at least 5.1 is available because I can watch movies with AC-3 and ffdshow plugins to get multi-channel audio. In the game options I have 5.1 set but I think there's a disconnect between the game and Windows audio controller. I'm using two Radeon HD 3850s in crossover mode and had to install the Realtek HDMI Audio driver separate from whichever software version I installed when I configured the setup about 6 months ago. The most recent version of Sapphire's ATI CCC didn't work properly so I had to revert to an older version. I do have an Audigy 2 ZS Platinum that is installed but not active. I've read in numerous places that the stereo analog outs (7.1 channel 3.5mm cables) would not work well with a receiver and would pick up static, not to mention the fact that they would need to go from 3.5 mm to RCA. Any thoughts on this problem?

Thanks for the reply. I'm still using XP Pro on that computer and I'm not sure what the channel setting is set to in Control Panel, but my guess would be 5.1 so I will double check. For playback devices I have my Audigy and the Realtek HDMI available for selection.

I just found this from a different section of the forum, so it seems I will only be able to get stereo PCM from the video card.

HD Decoding with UVD
One of the features lacking in the 2900 XT was the new UVD video decoder engine. UVD provides hardware acceleration of H.264 and VC-1 high definition video formats used by Blu-ray and HD DVD. The video processor allows the GPU to apply hardware acceleration and video processing functions while keeping power consumption & CPU utilization low. When the HD 2900 XT was released it took the press by surprise that the low-cost HD 2400 and 2600 where able to post-processes and accelerate HD streams like VC1 and H.264 fine while the 400 USD counterpart missed that engine and thus that translated into much higher CPU utilization.

That no longer the case, we ran a HD-HQV test and noted sheer decoding perfection on both the HD 3850 and 3870. Low CPU utilization whilst scoring a maximum of 100 out of a 100 points. One other improvement has been made as well you can now upscale your 1920x1080 streams fine towards for example a 2560x1600 sized monitor (no more black borders).

HDMI & HDCP compatibility
Obviously the entire HD 3000 series of cards will offer HDMI connectivity with the help of a DVI adapter or native with a HDMI connector integrated into the card, all cards fully support the DRM cancer called HDCP. Unlike most current HDMI implementations on PCIe graphics cards, this HDMI solution also incorporates audio functionality into the GPU.

Your series 3000 card can directly output audio over HDMI – removing the need of a separate sound card over your HDMI connector. Where it'll output that sound in 16-bit PCM Stereo sound or AC3 5.1 compressed multi-channel audiostreams as Dolby Digital and DTS. A feature, especially for those who use their PC as a HTPC and are connecting HDMI towards a HDMI receiver.
So with the Series 2000/3000 you'll receive a DVI-to HDMI adapter which, and make no mistake here, will carry sound over HDMI. That's unlike current DVI-HDMI adapters and cables which do not carry sound. Fantastic if you are watching a Blu-ray movie, simply connect HDMI towards your HDTV for PCM sound, or connect it through a TrueHD/Dolby HD receiver and get that sound lovin' going on through that receiver of yours. All with one simple cable.
Here we can see that DVI to HDMI dongle that is supported with the HD 3000 series Radeon graphics cards.

I have to note that some board partners are now slowly making to move to integrate a HDMI connector on the graphics card. TUL (PowerColor) for example submitted a card today that has HDMI integrated.

I ran the cables from computer to receiver and it works good so far.

Does anyone think the onboard audio controller could be better than the Audigy 2? The onboard chip is a Realtek ALC1200, 8-channel High Definition Audio CODEC and it has its own separate analog ports like the Audigy, with an addtional digital S/PDIF Line out.

I quick search shows more people on favor of the A2zs but others say it's a toss up. I'll leave it as I have it since it's working properly at the moment.

I have 5.1 working properly using the analog outputs on the back of the Audigy 2 - 3 mini stereo to R/L RCA cables, going to the multi-channel input on the receiver. If my room was larger I would have 7.1 surround, but I sit right in front of the rear speakers so I can't justify more speakers. With the analog out the game, and movies, function just like if I were to have Creative's Audigy speakers systems with their "special" cables from card to sub and speakers. I have the game settings set to 5.1 and, as I said, it's working well. I would prefer if I could use the HDMI on my graphics card but it's a bit older and will carry compressed (AC 3, etc.) to the receiver. For DirectSound it will only send stereo to the receiver. But I seem to have everything working well so I will leave it alone. Thank you all for the suggestions.