Either you could use a search and destroy waypoint or similar, together with fire at will etc with only a bomb payload (i havent tested that)
Or you can use a trigger(or waypoint) and the "fire" command ( unit fire ["muzzlename","ammo"] ).
You could possibly tie that with gamelogics tied to waypoints etc for a bit of extra effect like flying enemies, secondary explosions and similar)
Could do the above with coded scripts also - but im clueless on that part, why i mention gamelogics.
-Tet
I