Need help with an i-pac 2-player issue

[toastboy]

I have an i-pac joystick-to-keypress adaptor running 2 arcade sticks, with the default mame mapping.
https://www.arcadeworlduk.com/pages/IPA ... Table.html

Everything works great except P2's SW5, which is letter "i" in the mame map. Think of it as medium-kick in street fighter II.
Pressing SW5 outputs the correct character "i", but Mister does not interpret it as SW5, so there's no medium kick for P2.

By using a USB keyboard, I've managed to find what Mister expects for P2's medium kick button, and it's "e''.
That key is not part of the mame mapping provided by the i-pac at all, so I can't just rewire my way around the issue.

How can I redefine mame's expectation for P2's SW5/medium-kick input?

If that's not possible I suppose I can create a custom map for the i-pac, but it's a pain as I have an old ps2 i-pac, don't know where the tools are, etc.....
Would be nicer just to fix that one button with a mister setting change.

[toastboy]

NVM - I managed to get the legacy programmer to work on my ipac.
https://www.ultimarc.com/software-for-older-boards.