Changing the "Sound Environment"

[[VC]CaptainValor]

The question is simple: how should I go about injecting a new sound file for the "sound environment"? (the sound loop that plays in the background of all levels, eg. the wind in SW) The [snde] tag doesn't appear to have an HMT plugin, but it contains sound files just like those in the [snd!] tag. You can see them when you batch extract.

This is going to be an important part of a mod I'm working on for Hang em High, so I'm hoping I can figure it out.