I realise this is an old converstation but I'm trying to find a solution myself. The problem with that product you linked to is that it converts 5.1 CH HDMI input to stereo output via optical/Toslink, so no good for surround sound systems. Personally I'm looking to convert HDMI output to separate HDMI video with optical output of 5.1 CH. My TV optical output also outputs stereo only, and with a huge delay compared to the video signal on the TV so it's not ideal either.