How do I make a Kotor 1 range weapon upgradeable?

[Todd Hellid 16]

I'm looking to make the Mandalorian Heavy Pistols from  Weapons of the Old Republic mod upgradeable. Can someone help me with this please?

[DarthParametric 3,785]

Open the UTI in the KOTOR Tools Item Editor, go to the Properties tab, add a new property, in the property editor window that pops up, choose a property type, for example bonus damage, set any other variables as appropriate (like subtype, value, etc.), then in the "upgrade required to activate" section, choose the appropriate weapon mod from the drop-down list.