HEAT grill to medium heat.
PLACE half the ribs in single layer on large sheet heavy-duty foil. Mix sugar and seasonings; rub half onto both sides of ribs. Bring up foil sides. Double fold top and one end to seal packet. Add 1/4 cup water (or 3 to 4 ice cubes) to packet through open end. Double fold remaining end, leaving room for heat circulation inside. Repeat to make second packet.
GRILL on covered grill 45 min. to 1 hour or until ribs are done. Remove ribs from foil; discard foil.
RETURN ribs to grill; brush with barbecue sauce. Grill 15 min., turning occasionally and brushing with sauce.