It may be an issue of the 'profile' that the WDTV is providing to the server, to tell the server what media it can support. If it is incorrectly saying it doesn't support WAV, the DLNA server shouldn't present WAV files to the client.

Does it play FLACs? If so, I'd convert all your WAV to FLAC; unless you really need WAV, it's a poor format to use, since it has no compression, and its support for metadata is poor.

Not all Players support the same formats over DLNA as they from local/attached drive.

MM UPnP / DLNA looks very nice on a WDTV, I'd really like to able to use it MP3's work great

But...when I select a WAV file nothing happens.

It looks like a WDTV should be able to play WAV files, it will play them from the USB drive attached but it won't play them over UPnP / DLNA.

Anyone had success with any player using WAV's over UPnP / DLNA ?