Thank you and sorry for the late response, didn't have much time to fiddle around with breadbox lately. The joystick functions can't be mapped to the keys, as far as I have seen. I have cycled through the option a couple of times, all it shows are keypresses. So if there's an easy fix, I'd be more than happy! I also looked up how frodo is configured. Within the ini-files, each keypress is assigned to a numerical parameter. If the joystick directions are also handled this way, I could easily edit the file.
But there's no way to monitor what number represents "joy up" and trying it out by restarting breadbox with random numbers set in the ini file is a bit too much. If there's an undocumented option, it would be just perfect.