How to handle Arcane Missile procs?

[mbox_bob]

So your question is, can I do something [random number of times] when I don't know how many [random number of times] I want to do it?

I thought you could look into http://wow.gamepedia.com/API_GetSpellCharges, BUT it indicates that Arcane Missiles will always return 0. There are a couple of other functions that might report whether it is enabled or not, so you could just keep casting until it is not enabled, if the other functions happen to work.
http://wow.gamepedia.com/World_of_Wa...pell_Functions
Possibilities are IsUsableSpell or GetSpellCooldown (this might be stretching it, but hey don't know unless you try), or even IsSpellOverlayed (if you have the spell activation overlays enabled).

Of course seeing as I have NO EXPERIENCE with WOW macros, this may not be possible at all...