Combine the BBQ sauce, honey and mustard in a bowl and mix well. Place alternating groups of shrimp, sea scallops and mushrooms on the skewers. Place completed kabobs in a baking pan. Spoon the marinade over the kabobs and allow to set for 12 hours (or over- night) in the refrigerator. Grill over direct heat for 7 to 8 minutes or until the shrimp have turned pink, turning frequently to prevent burning. Baste with marinade and use a covered grill to insure smokey flavor. Garnish with fresh fruit.