Well, how do you make footsteps for the characters when they walk?
Also, how do you change the sound of the footsteps depending on what you're walkng on (like go from grass to sand, etc.)?
In the View editor, you can set a sound for each frame of the view. Click the text that says "NO SND" under the frame.
Not sure if you can edit the view sounds on the fly, but, at worst, you could change the view to one with the right sounds when the surface changes. I wouldn't want to do that for more than a couple of surface types though.
i do believe you can change the sounds that it is referencing by checking what region they are on.
BFAQ'ed: http://bfaq.terran-x.com/#audio05 :)