You'll want to have a lot of gold before giving this one a shot. When you talk to Omiduil he will tell you about your past and you will get experience each time you do so. What you do need to do is save your game twice, once before you talk to him and once after you talk to him. Load the game where you haven't talked to him, and import your character from the game where you have talked to him. Repeat process of paying gold for EXP points. This will also work with the Cleric when she talks to the priest of helm.