In large pot, cover pinto beans and onions with water. Over medium high heat, bring to a boil, turn heat down and continue cooking, stirring occassionally and adding water as needed until beans are almost totally tender.
add fresh green beans, ham and seasonings, more water to cover and continue cooking, covered.
when beans are tender, add potatoes. Make sure there is enough liquid covering vegetables as it cooks down.
when potatoes are fork tender. Add butter. stir in and dish out.