MARINADE: Combine chopped onion, chopped garlic, chopped parsley with the Tiger Sauce Worchestershire sauce, steak sauce and dry mustard. Mix well. Make slits into roast and rub sauce well into and over the roast (a basteing syringe works well to place suace into slits). Allow to sit in the refrigerator for 6 hours (or overnight). TOMATO SAUCE: Mix tomato paste and the brown sugar very well and set aside. Cook roast in a covered grill until the internal temperature of the roast is 170 degress. Brush with Tomato Sauce when done and serve. NOTE: Tiger Sauce is a brand name of sweetened hot sauce.