Sirloin Kabobs

1/4 cup soy sauce
3 tbsp. light brown sugar
3 tbsp. distilled vinegar
1/2 tsp. garlic pepper seasoning
1/2 tsp. garlic powder
1/2 tsp. seasoned salt
4oz 7-Up
2 lbs. beef sirloin steak, cut into 1 in. cubes
2 green peppers, cut into 2 in. pieces
1/2 lb. fresh mushrooms, stems removed
1 pint cherry tomatoes
1 pineapple - peeled, cored and cubed

In a bowl, mix first seven ingredients. Reserve 1/2 cup for basting. Place steak in a plastic bag. Cover with marinade and seal. Refrigerate for 8 hours. Bring water to a boil. Add peppers, cook for 1 minute, drain. Preheat grill for high heat. Thread steak, peppers, mushrooms, tomatoes, and pineapple onto skewers. Discard marinade. Lightly oil the grill grate. Cook kabobs on the grill for 10 minutes, or to desired doneness. Baste frequently with reserved marinade during the last 5 minutes of cooking.