AAC multichannel without breaking WMC recording thumbnails

[xlxcrossing]

I have Shark007 setup to decode/encode everything to multichannel to my receiver. I use file types AVI, MKV, and MP4. The only way though I can figure to continue decoding multichannel audio in MP4 movie files is to use FFDShow which would require disabling Microsofts Video Decoder which in turn breaks thumbnailing for Media Center recordings. If I switch to Microsofts video decoder and FFdShow for audio the file won't play. Anyone know how I can make it all works without sacrificing anything?