How do I get Merchant Clothes without stealing?

The Locke character in my Hack doesn't use the Steal ability, and I've been trying to get the Merchant clothes with a thiefknife, but I can't seem to do it. I tried to edit the Merchant's steal/drop items, but there are no merchant clothes, and they don't seem to be a unique item because I can't find Merchant Clothes or the Guard's Clothes in the list. What kind of items are these, and how can I obtain them in a hack that doesn't have Locke steal?