Re: Suppressive fire
The script is going to use a "fired" EH to catch the bullet, then an "Any Present" trigger to create the list of all units in the game. It will then check out the distance between each of these units and the bullets final impact point - if this is 20m or less then the target unit will be playMoved prone or doMoved 200m away from the firer, with random hold fire and hold move orders thrown in for variety.
Of course the player or AI group leader will be able to override all of this but that will take time. The idea is to have various units all in various stages of cowering and or fleeing al over the battlefield.
Re: Artillery sounds.
Check out Sounddogs.
http://www.sounddogs.com/start.aspJust type in your required sound effect (eg - whoosh, zoom, kaboom) or some other word (artillery, shellfire etc) and click on the sound icons for each returned sound. Unless you pay you can only get short samples but I've never had any problems with that.
The returned files will be in wma format but google around and you should be able to get a freeware wma to wav converter.
cheers
roni
EDIT - fixed typos