Cut beef steak into 1-1/4-inch pieces. Combine seasoning ingredients in large bowl. Add beef, mushrooms and bell pepper pieces; toss to coat.
Alternately thread beef and vegetable pieces evenly onto eight 12-inch metal skewers, leaving small spaces between pieces.
Place kabobs on grid over medium, ash-covered coals. Grill kabobs, covered, 7 to 9 minutes (over medium heat on preheated gas grill, covered, 9 to 11 minutes) for medium rare (145°F) to medium (160°F) doneness, turning once. Season kabobs with salt, as desired.
Meanwhile combine sauce ingredients in small bowl. Serve with kabobs.