SPRINKLE gelatine over water in small saucepan; let stand 1 minute. Cook on low heat 5 minutes or until gelatine is completely dissolved. Remove from heat; cool slightly.
PLACE sour cream, avocado, green onions, lemon juice, hot pepper sauce and dressing mix in blender container; cover. Blend on low speed 1 minute. Gradually add gelatine mixture, blending well after each addition. Place in serving bowl; cover.
REFRIGERATE several hours or until set. Top with tomato and olives. Serve as a dip with fresh vegetable dippers.