STIR boiling water into dry gelatin mix in large bowl at least 2 min. until completely dissolved. Stir in 7UP soda. Refrigerate 1-1/2 hours or until thickened (spoon drawn through leaves definite impression).
STIR in mandarin oranges and strawberries. Pour into 9x5-inch loaf pan sprayed with cooking spray.
REFRIGERATE 4 hours or until firm. Remove from loaf pan. Store leftover gelatin in refrigerator.