Melt butter in a saucepan over medium-high heat. Add onion, garlic, and jalapeno pepper, and saute 2 to 3 minutes or until tender. Stir in ketchup and next 3 ingredients; bring to a boil. Reduce heat, and simmer 20 minutes. Reserve 1/2 cup sauce for dipping, if desired.
Cut pork ribs into 2 sections, and sprinkle evenly with salt. Brush both sides of ribs with sauce.
Prepare a hot fire by piling charcoal or lava rocks on one side of grill, leaving other side empty. (For gas grills, light only one side.) Coat food rack with cooking spray, and place on grill. Arrange food over empty side (unlit side of gas grill); grill, covered with grill lid, 2 hours, turning and basting every 30 minutes.