Add Armor Locations?

Short version: How do I add new Armor Locations to the editor's choices for new armor?

Long version:
I am trying to add all the armor (and eventually all other equipment) in Arsenal, and have a problem. Much of the armor is meant to be worn as a "set", with their protection being additive (instead of only the best counting, as normal).

To some degree, this can be accomplished by choosing an "armor location" in the editor, but the only options are "Full helmet", "helmet", "mask", and "shield".

A suit can technically be done this way by setting the pants as the armor, the shirt as a helmet, the jacket as a mask, and some other item as a shield, but I would much rather simply define some new armor locations, such as "Pants", "Shirt", "Jacket", etc. especially since some (eg. Form Fitting Armor) can explicitly be worn under any other armor suit with additive protection.

In order to handle the armor stacking, my plan for the piecemeal armor in Arsenal is to make the individual pieces into modifications or accessories that can be added to the base item (the base version of these armors may end up being free, with all the cost in the modifications).

That way, even though armor in Shadowrun doesn't normally stack, when you add multiple pieces of something like the Mortimer of London line, they will stack.

That's actually a pretty good fix, it would also allow people to mix and match the outfits.

I.e. Mortimer pants, and throw in some Zoe stuff... very nice