Those WTV files are unencrypted MPEG files. I can play them just fine any any other set top box I have including XMBC with no issues. I understand they can be encrypted sometimes and may not be playable but in this case they are just simple MPEG files.
If they’re simple MPEG files, then just change the extension to .mpg and they will play.
Well if I rename the file then build in features of Windows Media Player will stop working like housekeeping etc.