yeah, to jump start you B_O, to find the rocket, then the script used something like
_rpg = nearestObject [_unit,_ammo]
where _unit was the unit who fired and _ammo is the type of ammunition that was fired. It is all initiated out of an event handler. Also, it used getPos to find when the rocket was .21 metres off the ground, then froze it.
That part of the simulation would be the difficult part, trying to find how close to the helicopter the RPG is.