Do all HD TVs support 5.1 AC-3 over HDMI? Do they downconvert to stereo? I am trying to understand a request to have an IPTV STB downconvert AC3 to stereo before it is sent over the HDMI audio. The only scenario where this request makes sense is if not all HD TVs can handle 5.1 over HDMI. My level of ignorance here is pretty large :). thanks! Doc McClenny