Place sliced steak in a large resealable plastic food storage bag. Spoon in 4 tablespoons of the grill sauce. Turn to coat meat. Refrigerate 2 hours.
When ready to prepare, soak noodles in hot water for 10 minutes.
Heat a large nonstick skillet or wok over medium heat. Add 1 tablespoon of the oil and the broccoli. Stir-fry for 5 minutes, stirring frequently. Add 1/2 cup water and cover. Continue to cook for about 3 minutes or until tender. Remove broccoli from skillet and reserve.
Wipe out skillet and add the remaining 1 tablespoon oil. Add marinated beef and stir-fry on high heat for 2 minutes.
Blend together the broth, cornstarch, remaining tablespoon grilling sauce, orange juice and zest. Add to the skillet with the beef. Stir in broccoli. Return to a simmer and cook for 1 minute or until thickened and broccoli is heated through. Drain noodles. Stir into skillet and cook for an additional minute. Serve immediately, garnished with orange slices, if desired.