I've read the Wiki but unfortunately I have checked all of that.
My A/V receiver in the living room works very well with other players and 5.1 output, even using ffdshow for pass-through in MCE for DTS and AC3 sound in movie files.
In the Media Center settings I have selected realtek digital output as the default sound device. In control panel I have set it to predetermined as well. Doing a test in windows control panel outputs 5.1 sound.
I will try more combinations tonight.
Anyone has a suggestion or ideas? thanks in advance.