When you open a UTC file in KotOR Tool, and you open the inventory, there are two menus. One is labeled Standard Items, the one you see in game, where you choose the gear the character is wearing. The other is labeled Natural Items, which is what Fair Strides talking about. You can't see this screen ingame. This menu shows the items that the developers put on some droids and other creatures throughout the game so that they would be immune or resistant to certain abilities.
These items are not considered equipped. They're considered a natural part of that creature. They don't override anything because the game puts absolutely nothing in those four slots. So if you want to give yourself a feat in KotOR, the easy way to do it is to make a new item, using one of the aforementioned natural items (Fair Strides mentioned g_i_crhide001.uti) as a base, and adding the proper parameter.
Then, following with the scripts Fair Strides has given, the end result should be the PC and Bastila dueling with lightsabers instead of swords.