Unless you're adding in new races or new sound files, the only thing you should have to do is replace the sound files that are already there.  Just make the sound you want and make sure it's relatively in the same format and name it the exact same thing as the sound file you want it to replace.  I replaced all the music files in one of my mods and that's all I had to do, replaced a few sounds too.

You shouldn't have to 'edit' anything, only replace. (and by replace obviously I mean put files in the mod folder with the exact same name as the sounds that you're overwriting.)

I did it with Sound forge 10.

Now I know the problem was that my new sounds were stereo but sins only plays them mono, i merged left and right channels and now they are playing fine