I had it working prior with FFDShow, an older version of LAV, and a media player. I wanted to switch to WMC along with Media Browser like Assassin has in his blog and since I always output to a receiver or processor, I just need it to bitstream, no need for codecs.
I uninstalled the older LAV as well as FFDShow and then proceeded to follow Assassin's instructions. I downloaded the newer LAV, installed it and then loaded Graph Studio to check it. I also downloaded Media Browser and setup WMC as well, even though LAV isn't showing up for the TrueHD tracked files.
Now here's an interesting piece of info - WMC/Media Browser will show all the files and the cool metadata, etc... It will play the MKV's with TrueHD (but not pass it via bitstream to the processor), howevever it will not play the DTSHD MKV's and gives me a "File not found, it must have been moved" error (or something similar). To me this points to LAV not working correctly but not sure why.
I uninstalled the LAV and re-installed the prior older version (but not the FFDShow) and still no luck, so I'm kind of stuck. I could re-add FFDShow and see how that goes but I don't want/need the codecs so I was hoping I could just get the simple/pure setup that Assassin detailed working.