Preheat oven to 350°F. Brown ground beef in large skillet on medium-high heat. Drain fat. Stir in Seasoning Mix, tomato sauce and ketchup. Bring to boil. Reduce heat to low; cover and simmer 5 minutes.
Remove rolls from package but do not separate. Cut entire package of rolls in half horizontally, leaving bottom half slightly thicker than top half. Place bottom half of rolls in 13x9-inch baking dish, cut side up. Spread meat mixture evenly over rolls in dish. Sprinkle with cheese. Place top half of rolls, cut side down, on top of cheese.
Brush tops of rolls with butter. Bake 10 minutes or until heated through and cheese is melted.