Bring vegetable broth and vinegar to a boil. Cut carp in 2x3 inch pieces. Add fish, celery, carrot, leek, onion, and mushrooms. Bring to boil, reduce heat, simmer about 5 minutes. Remove fish and keep warm. Reduce liquid to about 1 cup. Add cream, sour cream, salt and pepper. Bring to a simmer. Simmer without boiling for 15 minutes. Stir in te dill and spoon over the fish.