Mix vegetables, vinegar, pepper and garlic powder in medium bowl. Bring tomato juice to boil in small saucepan. Stir into gelatin in large bowl at least 2 minutes until gelatin is completely dissolved. Refrigerate 1-1/4 hours or until slightly thickened (consistency of unbeaten egg whites).
Stir in vegetable mixture.
Pour into 4-cup mold or bowl sprayed with cooking spray.
Refrigerate 3 hours or until firm. Unmold.
Serve with salad greens and garnish with tomato and cucumber slices, if desired.