Thaw scallops, if frozen. Fold a 36x18-inch piece of heavy foil in half to make an 18x18-inch square. Place squash and/or zucchini and carrots in center of foil. Sprinkle lightly with salt and pepper. Bring up 2 opposite edges of foil; seal with a double fold. Fold remaining ends to completely enclose the vegetables, leaving space for steam to build. Grill vegetables on the rack of an uncovered grill directly over medium heat for 15 to 20 minutes or until vegetables are crisp-tender, turning vegetables occasionally.

Meanwhile, for the sauce, in a small bowl combine the sweet-and-sour sauce, basil, Thai seasoning or five-spice powder, and garlic. Transfer 1/4 cup of the sauce to another bowl for basting. Reserve remaining sauce until ready to serve.

Rinse scallops; pat dry. Halve any large scallops. On four 8- to 10-inch skewers thread scallops. Place kabobs on grill rack next to vegetables the last 5 to 8 minutes of grilling or until scallops are opaque, turning once and brushing with basting sauce during the last minute of grilling. Serve scallops and vegetables with the remaining basting sauce. Makes 4 servings.