I've been known to use Symettrical (sp?) lattices, and texture them with volumes. Try Menno's Fire, it's a good flame mat, and standard Clouds mats for the smoke. I'd think you'd get a mixture of the 2 in a real explosion. Maybe playing with the transparency of the smoke will help. This question has come up before, and an explosion is a dynamic event; you can choose how far along the destruction sequence you want to go..
them boys blowed up real good..
-Redneck Rampage..;)

I wish I'd said that.. The Staircase Wit

anahl nathrak uth vas betude doth yel dyenvey..;)