With the hardened front shafts you need to use the larger side gears from the rear end of the Samurai. You can either get a rear end with a locker in it or just buy a locker for the rear end with side gears.
If you are referring to the Kam Locker then I don't believe you can use it in the front end. Maybe if you had some custom front shafts made up, but the Kam uses custom rear shafts.