Edit: Nevermind, I solved my own problem.

It is generally good practice to post your solution so that other people who are having the same problem can resolve it quickly.

Having done this before myself, I expect the solution involved the use of the http://www.creationkit.com/DropObject_-_ObjectReference function.

Cipscis

Okay, I'll post the solution then. When objects are dropped with DropObject, they often turn invisible (I don't know why?) unless they're moved by the script. So after I force an item to be dropped, I move it in front of the actor and it works like that.