In saucepot, prepare ziti as label directs. Meanwhile, cut green peppers, carrots, celery, and onion into 1/2" pieces. In nonstick skillet over med. High heat, in hot salad oil, cook vegetables til lightly browned. Stir in 1/4 °C. water; continue cooking over med. Heat til vegetables are tender crisp. Preheat oven to 375 F. Drain ziti in colander; set aside. To same saucepot, add cooked vegetables; stir in crushed tomatoes, vegetable juice, sugar, salt, and oregano; over high heat, heat to boiling. Remove saucepot from heat; stir in cooked ziti. Reserve 1 C. shredded mozzarella for topping. Into ziti mixture in saucepot, stir Parmesan cheese and remaining mozzarella. Spoon mixture into shallow 4 qt. Casserole; sprinkle with reserved mozzarella cheese. Cover casserole and bake 30 minutes or til cheese melts and mixture is hot and bubbly.