Just in case anyone here is still struggling with the wrong buttons showing up like I was, I edited the file in GIMP to make it show up with X as confirm, O as cancel, Triangle as Menu, and Square as the triple triad challenge button.
(If it doesn't show up automatically, the first link is what my controls look like and the second link is the actual picture you should drop into the sy/sysfld00 folder.)
I'm using a Steam Controller with everything mapped to keyboard buttons and this works for me! Hope this helps others because I know I was frustrated at the buttons not showing up how I wanted them to. http://imgur.com/a/IZIJ1http://imgur.com/a/yFDXV
Edit: When you save the image from imgur, make sure you save it as sysfld00_17 before you drop it into the sy/sysfld00 folder. It should save as PNG automatically but you'll need to set the name yourself.