Wash pumpkin; cut a 6-in. circle around top stem. Remove top and set aside; discard seeds and loose fibers from inside. Place pumpkin in a large Dutch oven. Fill with boiling water to a depth of 6 in.; add 1/2 teaspoon salt. Cover and simmer for 30 minutes or until the pumpkin is almost tender but holds its shape. Carefully remove and drain well; pat dry. , In a large skillet, cook the beef, onion and green pepper over medium heat until meat is no longer pink and vegetables are tender; drain well. Cool slightly; place in a large bowl. Add rice, tomato sauce, ham, eggs, garlic, oregano, pepper, vinegar and remaining salt. , Place pumpkin in a shallow sturdy baking pan. Firmly pack beef mixture into pumpkin; replace top. Leaving pan uncovered, bake at 350° for 1 hour. Let stand for 10 minutes. Remove the top; if desired, use paper towel to remove excess moisture from top of meat. Slice pumpkin into wedges.