In large saucepan, cook ziti to desired doneness as directed on package, adding broccoli during last minute of cooking time. Drain; return to saucepan.
Meanwhile, heat oven to 350°F. Spray 2-quart casserole with nonstick cooking spray. In medium saucepan, combine 1/2 cup of the milk, flour, salt, hot pepper sauce and garlic; stir with wire whisk until smooth. Stir in remaining 1 1/2 cups milk. Cook over medium heat until mixture boils and thickens, stirring frequently. Remove from heat. Add cheese; stir until melted.
Add cheese sauce to cooked ziti and broccoli; mix well. Stir in roasted peppers. Spoon into sprayed casserole. In small bowl, combine bread crumbs and melted margarine; mix well. Sprinkle over top.
Bake at 350°F. for 20 to 25 minutes or until casserole is bubbly and crumbs are golden brown.