PREHEAT oven to 375°F. Mix steak sauce, teriyaki sauce and mustard until well blended.
OPEN butterflied steak onto clean work surface; press down to flatten. Spread 1/4 cup of the steak sauce mixture onto steak. Arrange snow pea pods, pepper strips and onions on the steak, parallel to the short ends of the steak. Roll up steak from one of the short ends; secure with wooden toothpicks or tie closed with kitchen string, if necessary. Place, seam side down, in greased 13x9-inch baking pan. Top with the remaining steak sauce mixture.
BAKE 40 to 45 minutes or until cooked through, brushing with the steak drippings every 15 minutes. Let stand 5 to 10 minutes before cutting into slices to serve.