Surround Sound Works Via HDMI, But Not WMV, No Audio

I've got a bit of a problem with my audio with my new installation of Windows 7. Previously I had Vista installed, and had no problems with my Realtek HD audio. Installed Windows 7 everything looked good, then realized my Sony A/V receiver model SA-WCT100 was not outputting my movie collection in surround 5.1 like it use to using Vista.

I figured, that�s cool, probably need to install ac3filter_1_51a, I had to in Vista, and it worked a treat when I enabled SPDIF pass through. I guess I should mention I�m using HDMI all the way through, from my PC to the receiver, from the receiver to the LCD. Well, that didn't fix it, everything still plays in stereo. After scratching my head and clicking here and there, I finally found a little tab in the sound settings of my Realtek HDMI setting called 'Custom'.

I selected it, it said to enable AC3, DTS, etc click this box will require a restart. I said awesome, sounds like just what I need. I clicked, and rebooted. I went into WMC, and setup my audio wizard again, and selected 5.1, and tested, and this time it reported 5.1 on my Sony receiver as before it only showed 2 channels (Stereo). I played some of my DVD rips, and bam my DVD rips were playing surround sound again.

I was like that was easy enough. I went to test my Blu-Ray rips that I had converted to WMV HD using TMPGEnc Xpress 4.0, and the video started to play, and I was like, wheres the damn sound. I noticed on the receiver, it didn't report anything for sound. I had no idea what was going on. My surround sound was finally working for everything, but my WMV HD videos had no sound output. I mean I can't even get stereo or anything out of them now. At least before the WMV played in stereo, now I can't hear anything.

Please someone tell me what could be the problem, I don't know what else to try. I don't want to have to revert back to stereo, and disable the magic box under custom in my sound setting.

I have downloaded the latest Realtek drivers form Realtek, version 2.35 for the ATI HDMI audio, and the Digital Audio. I also have the latest drivers for my integrated Radeon 3200 graphics card. I read that sometimes a high resolution can affect the audio, so I lowered my resolution from 1080p, and that didn't help, which I figured it wouldn't.