Make marinade by mixing soy sauce, brown sugar, distilled white vinegar, garlic powder, seasoning salt, garlic pepper, and Sprite.
Set aside half cup of this mix for basting and place in plastic bag or in a tupperware.
Add cubed steak to a gallon-size Ziploc bag or tupperware and cover with the remaining marinade. Seal and refrigerate overnight, or for 8 hours up to all day.
Preheat grill for high heat and prep veggies by coating with a little olive oil and garlic salt.
Thread steak, green peppers, zucchini, tomatoes, and pineapple onto skewers, alternating the pieces.
Cook kabobs on lightly oiled grill and cook for 10-12 minutes. Baste with reserve marinade while cooking kabobs and serve warm.