I was talking to LostInSpace awhile back, and we got to messing with the audio files, when we figured this out. I decided since I'm not going to do anything with it, I'd go ahead and post it.
If you don't know how to extract audio, check
this.
First of all to reimport you just need a .bat file with
quickbms -w -r speechbms.bms Music.bin(the bin you want to import into) folderwithaudioormusicfiles
pause
This will only allow you to say, replace music, not add. The file also needs to be smaller than the original, or it will not work.
It seems to work fine, though I haven't really tested it, because I can't modify the xsb/xwb files.
The files have a header. "SDBK" for xsb. "WBND" for xwb.
https://code.google.com/p/monoxna/source/browse/wiki/XnaFrameworkAudio.wiki?r=346I think this,
Microsoft XNA Game Studio, is what you want to use.
I can't install it though, it may only work for older windows, like XP. It should work for 7, though.
I don't know, this is just what I found. Someone might find it useful.
There's this too.
Getting Started with XACT