As to adding script command to add the DLC items, that's probably going to be a bit tougher, reason being the toolset doesn't pull in the DLC items automatically where one could view their tags. I hear tell that some folks have managed to open the ERFs for the DLCs and view items and stuff that way, but I haven't figured out how they do it yet, when I try to open those ERFs the toolset gives me an error. So I dunno about the OP, but for my own scripts I've been making I'm at a dead end myself for that stuff. Hope he has better luck!
thier tags? as in the item template? if so easiest way is using the toolset on a savegame that has the item, either equiped or in backpack
What exactly is this "toolset" that people keep mentioning, and where can I get it?
You need to go to the official page to dl the toolset.