Saute onion and garlic in butter three to four minutes. Add remaining ingredients and bring to boil. Lower heat and simmer uncovered for one hour, stirring frequently. For a smooth sauce, strain through a sieve. Preheat oven to 400. Remove excess fat from ribs and cut as desired. Place ribs flesh side up on rack of roasting pan. Sprinkle with salt, pepper, and curry powder. Bake for one hour basting with warm barbecue sauce every ten minutes. Serve with remaining barbecue sauce.