Combine Mayonnaise, Brown Sugar, Mustard And Seasoned Salt; Mix Well. Blend In Vinegar. Pour Into A Large Resealable Plastic Bag Or Shallow Glass Container; Add Pork. Seal Bag Or Cover Container; Refrigerate Overnight. Drain And Discard Marinade. Grill, Covered, Over Medium Coals, Turning Occasionally, For 20-25 Minutes Or Until Juices Run Clear.