Cut An Incision On The Beef Chunks And Push A Strip Of Pork Fat Into Each One. In A Casserole Dish, Combine The Beef Stuffed With Fat, Tomato Sauce, Soy Sauce, Bay Leaves And Beef Stock. Bring To A Boil And Simmer Until The Beef Is Almost Tender. Then Add Vinegar And Let Boil For A Minute Or Two. Add The Potatoes, Onions, Carrot, And Bell Pepper. Occasionally Stir From Time To Time And Cook Until Potatoes And Carrots Are Tender.