Cut The Roast In Half; Pierce Several Times With A Fork. Place In A Large Resealable Plastic Bag Or Shallow Glass Container. Combine The Next Eight Ingredients; Pour Over Roast. Cover And Refrigerate Overnight, Turning Occasionally. Drain, Reserving Marinade. In A Skillet Over Medium Heat, Brown The Roast In Oil On All Sides. Place Onion, Roast And Marinade In A Slow Cooker. Cover And Cook On High For 2 Hours. Reduce Heat To Low; Cook 6-8 Hours Longer Or Until The Meat Is Tender. Remove Roast; Shred Or Thinly Slice. Discard The Bay Leaf. Skim Fat From Cooking Juices And Transfer To A Saucepan; Bring To A Rolling Boil. Serve Pork On Rolls With Juices As A Dipping Sauce.