Heat a small skillet over medium-high heat. Add oil to pan; swirl to coat. Stir in annatto seeds, and remove from heat. Let stand 15 minutes. Discard annatto seeds, reserving oil in pan.
Place lemongrass and next 9 ingredients (through garlic) in a blender; process until finely chopped. Pour mixture into large zip-top plastic bag; add annatto oil and chicken pieces. Seal bag, and marinate in refrigerator at least 2 hours or up to 8 hours.
Preheat grill to high. Remove chicken from bag; discard marinade. Place chicken on grill rack coated with cooking spray; grill 19 to 20 minutes, turning occasionally.
While chicken cooks, place a small skillet over medium-low heat; add honey and butter, and cook 5 minutes or until butter melts. Baste chicken with honey-butter mixture. Cook chicken 5 minutes or until done, turning and basting frequently with honey-butter mixture.
Combine cider vinegar and remaining ingredients in small bowl, stirring until sugar and salt dissolve. Serve chicken with sauce.