I think the only formats that the gramophone supports are .mp3, .wav & configured OGG filles.< like the speech files.
Here is a link for you:
http://www.subsim.com/radioroom/showthread.php?t=132616
It's a mod that contains music from Das Boot, nive songs :p
Just activate it with JSGME and make sure it's in the mod file.
I think you may need other songs as well, i don't think that .wma file is supported.
Cheers