I'm going to take the lazy way out and not take a look myself, but I will tell you how to figure it out for yourself.
Go download infinity explorer, as it is very useful for looking at the game. Search for Morul's dialog (which you can find by searching for his .cre (creature) file). Once you have his dialog up, there should be some timers or things like that, or conditions for him to give you specific items. You can change these by enabling the console, and simply changing the global variables in game.
The explorer isn't very advanced, but it has a good interface. If you want to edit stuff, or search easier, try near infinity, or dltcep.