Playing Tivo File on WMP

[MaxJustMax]

I'm trying to play TiVo files on Windows Media Player(WMP) using my DS411j DiskStaion media server app.
The DiskStation server shows up on the WMP list of devices just fine and the Video directory shows up. I have one AVI file and several TiVo files in the Diskstation Video directory but only the AVI file shows up in WMP. When I map the \\diskstation\video directory to a device letter, all the files show up. And I can drag & drop at TIVO file onto the WMP. It plays fine.

So - How can I get the Media Server to show the files in WMP's media list?

Here are the things I've tried:
Enabled cusomized MIME types: "avi=video/x-ms-video,wav=audio/x-wav,TiVo=video/x-TiVo" then reindex.

The MIME type string was a wild-ass guess. Any better ideas?
I shouldn't think this would be too hard since the WMP plays .TiVo files.
Thanks,
MaxJustMax