Removing attack ground...

I've been looking for a way to remove the attack ground option from my artillery units. I've figured out that if you make the attack a missle attack, you won't have attack ground. However, the Burning Oil ability won't happen if the attack isn't artillery. What I want is to make some sort of nuke/explosion effect whenever a missile hits a building, and burning oil seemed to look nice. Any ideas, anyone?

EDIT: I couldn't get burning oil to work, but I got liquid fire to work, so now at least I have an effect on it. But is there a way to change the artwork of Liquid fire to look like burning oil, or flamestrike, or something? Basically, when I fire at a building, I want it to look like it's burning, or getting nuked.