Peel and devein shrimp, leaving tails intact. Thread shrimp onto 4 (10-inch) skewers.
Thread scallops onto 3 (10-inch) skewers.
Place shrimp and scallops on grill rack coated with cooking spray. Grill shrimp, uncovered, 2 minutes on each side or until done; grill scallops, uncovered, 3 to 4 minutes on each side or until done.
Remove seafood from skewers, and place in a large bowl. Add butter and remaining ingredients; toss. Serve immediately.
Note: If using wooden skewers, soak them in water for 30 minutes to prevent the wood from burning on the grill.