Raze:
The item editor does not create items; you need to have the item first. Check your inventory before leaving Divinity and make a note of the name of the item you want to edit (and maybe some of the stats, so you can tell the difference between similarly named items). The Well Made Skull Cap you edited could have been in a chest somewhere, etc.
Shall I include this into the Mirror site, Raze?
Kiya