Melt margarine over medium high heat in a skillet. Add onions, peppers, and garlic powder. Sauté for about 4 minutes.
Meanwhile, cook pasta according to box directions.
Heat sauce and combine with cooked hamburger and cooked sausage.
Use cooking spray to lightly grease a 13 x 11-inch casserole dish. Place 1/2 of the cooked pasta in the dish, followed by 1/2 the vegetables, 1/2 of the pepperoni and 1/2 sauce. Repeat another layer. Spread mozzarella cheese over top. Bake at 350 degrees F for about 45 minutes or until cheese is melted.