You can switch sounds only within one sub-group (by saying this I mean 0xsomething in snd_group_something). After you find the offset of WAVE string, you have to find the offsets to the both sounds and then switch them.
i dont know what any of that means but i get the general idea, sound hacking sounds very complicated.
and from what ive read my 64-bit wondows wont allow me to even do this stuff.