Soak dry beans overnight in water to cover.
Morning, add dry salt pork and simmer beans in water to cover until tender.
Mix cooked beans with onions, salt (unless salt pork has seasoned beans sufficiently), dry mustard, brown sugar and molasses.
Dice the cooked salt pork and mix with the beans.
Turn into a greased baking dish and add beer (to cover).
Cover dish and bake in a slow oven (350 deg.) about one hour, stirring twice during cooking.
Remove cover for the last 15 min of cooking.