Poked around with a hex editor for a little bit yesterday. Got interrupted before doing too much though.
Didn't find the location of the accept and back keys yet. Swapped out a couple that looked like they might be it, but they didn't work when I launched the game.
Pretty sure that I did find the text for the keyboard and dinput labels that are created on the fly.
This evening I'll try to swap in the letters that correspond to my button labels and see what happens. If it works, it will make the tutorials and story mode much more enjoyable on my cab. Doubtful it will be of much use to anyone else though.
I'll probably have to use U,D,L,&R for directions rather than arrow keys or else it will change the file size.
I also searched for mention of all the dll files that x360kb.ini can be paired with.
The only one in there is xinput1_3.dll
That is the one used for MKK and when trying to use x360kb with Injustice, I do get the "ding" sound that the file is being accessed.
So I'm pretty sure that is the correct dll file to be used.
EDIT: It does mention dinput8.dll also.
It's mostly over my head, but when browsing with the hex editor, I did notice some stuff where it looked like the game would look for some type of response from the xinput controller and if it didn't get it, it would then default to keyboard. I still think x360kb not working has something to do with getting the x360kb files to "hook" like the new version of x360ce.