In a blender, blend together soy sauce, banana ketchup, brown sugar, garlic, lemon-lime beverage, pineapple juice (if using), oyster (or hoisin) sauce, lemon juice (if using), pepper, and MSG.
Mix together pork and marinade and keep in the refrigerator overnight.
String the pork on the skewers.
Place in hot grill, grill approximately 4-5 minutes each side.
With the leftover marinade, boil over high heat in a medium pot for about 10 minutes. Strain and serve over hot rice.
Note: Skewers can also be cooked under the broiler in the oven.