Old School HTPC Gaming

With the advent of my HTPC sitting front and center in the living room, attached to the plasma TV, I quickly realized that I don’t feel like going upstairs to use my regular computer.  First off, it’s warm up there.  Second, even with 3 screens, it’s not the same as a 50" plasma.  Third, my home theater speakers are much better than the Logitechs.  So, I started playing Baldur’s Gate from the very beginning (again) a few months ago, on the plasma.  These old games don’t look very good on monitors with native resolutions of 1920×1200, but they do look quite nice on my 720p plasma at 1366×768, especially with EasyTutu installed, which allows you to utilize the higher resolution Baldur’s Gate 2 engine in BG1.

This leads me to a small dilemma.  My HTPC is using HDMI via an ATI 4650, through my receiver.  Due to this, I’m using onboard audio for gaming.  However, I can’t use the EAX features of the game without a compatible sound card.  Also note that I’m using 64-bit Windows 7.  Anyone know how to get EAX working under this scenario?