Trim brisket of excess fat. Rub fajita seasoning on brisket. Mix remaining ingredients with enough hot water to fill water pan of smoker. Place brisket on racks of smoker. Cook approximately 4-6 hours. Remove brisket.
Place in large pan. Cover tightly with foil. Cook in 170 degree oven for 10-12 hours. Cool. Chop. Mix with your favorite bar-b-que sauce. Return to oven and heat thoroughly. (Masterpiece Bar-B-Que sauce or Bull's Eye is good.)