x-wav isn't supported, and probably won't be. There are many formats of WAV file, and they don't have any sort of unique identifier, so telling which is which before calling mplayer for A2DP is kind of difficult. Also, most people use mp3 or some other highly compressed format these days so I'm not sure why we would want to go to the trouble of supporting it. It's not really a modern file format for music anymore.