So I've got this actor who needs to cast a spell in order to be able to use it's package correctly. I'm not exactly sure how to do this correctly.

Obviously I need to run it on the "Begin" stage using "Cast", that's the easy part. However, I can't get my spell in scope of the package. I'd need to set a property to do that, except from what I've seen I can't have properties inside packages.

So, how would I go about ensuring that my NPC casts a spell everytime they start using my package?

Well, you can set packages to have owning quests. So just do that, and have something like:

(GetOwningQuest as MyQuestScript).SpellCast(akActor)

And have your quest script something like:

Scriptname MyQuestScript extends QuestSpell property SelfTargetSpell autoFunction SpellCast(Actor NPC)    SelfTargetSpell.Cast(NPC)EndFunction

sure you can. on the fragment of the "begin" you can add a property for whatever it is you need