Making a new keyboard layout

[Kiyura]

Both of the keyboards I use with this computer work fine with the standard layouts. Most commonly, I use the Dvorak layout. However, would prefer to be able to create a custom layout as I have on Windows and Linux, since I am used to having the 'i' and 'u' keys swapped from their normal Dvorak positions. I also had some other modifications, but this one in particular affects my typing speed and comfort severely.

 

The problem is that when I try making a new keylayout file, for instance with an online utility (http://wordherd.com/keyboards/) or with the Ukulele program, it will not work. When I switch to the layout, none of the keys on the keyboard will register at all. A problem with the keycodes on non-Apple hardware?

 

I can't seem to find the file that contains the standard, included Dvorak layout. I had originally planned to just modify that. It's a very simple modification, and even if the file is binary I could probably do it with a hex editor.

 

I would greatly appreciate any suggestions regarding the location of the system's keyboard layouts, or the correct way to create a new one.