Place bean mix into a large bowl and cover with several inches of water; soak for at least 24 hours.
Drain completely.
Bring chicken stock to a boil in a pot large enough to hold the beans and, eventually, the ham bone.
Add the soaked beans; reduce heat and simmer until tender, about 1 hour.
Bring stock and beans back to a boil.
Add ham bone, onion, carrots, celery, garlic, and bay leaves.
Reduce heat to low and simmer until vegetables are soft, about 1 hour.
Add chopped ham, liquid smoke, and mustard powder.
Stir and let simmer until flavors blend, about 30 minutes more.
Remove ham bone from the soup.
Season with salt and pepper.