i think that you reed this: http://pcloadletter.co.uk/2011/04/05/5-1-channel-audio-through-headphones/comment-page-1/#comment-15657 you don't need ffdshow any more with cyberlink audio decoder PDVD13, it can work with AC3 audio, i tray it witch MPC-HC and it worked perfectly and the option...

because of the variation of the hardware, try to instal the pack into your virtual machine, you can tick just the audio decoder, after that you got all necessary files to the audio decoder, i dont understand what's the probleme with my installer, Anyway 1- when you put those files it necessary...

Cyberlink Audio Video Codec Pack from PowerDVD 13 Ultra work with   Video : MPEG2 / MPEG4-H.264 / VC1 Audio : AC3, DTS 24/96, Dolby ProLogicIIx, Dolby DigitalEX, TruSurroundXT, CLMEI2, Dolby Virt-Speaker, 5.1, 7.1   Download:   http://uptobox.com/jh8j2cwxojkg