Preheat oven to 400°. Bring water to a boil in a medium saucepan. Add lima beans, bell pepper, and onion; cover and cook 5 minutes. Drain. Combine lima bean mixture, ham, cheese, Worcestershire sauce, and corn in a bowl; stir well. Spoon into a 2-quart casserole coated with cooking spray. Cover and bake at 400° for 20 minutes.
Combine milk and green onions in a bowl, and stir in baking mix. Drop batter by spoonfuls onto ham mixture to form 6 biscuits. Bake, uncovered, 20 minutes or until biscuits are golden.
Note: You can also assemble the casserole ahead of time, omitting the biscuit topping; cover and chill in refrigerator or freeze (thaw the frozen casserole overnight in the refrigerator). Let the casserole stand at room temperature 30 minutes; add the biscuit topping, and bake as directed.