This document assumes you already have a radio box key (D1 - D24) that doesn't fit your existing lock.

1)  Remove nut and handle

3)   Pull lock assembly off of door.

4)  Turn lock over.

CAUTION!  The next step will expose two springs under tension.
Wear safety glasses and don't lose the springs!

5)  Remove these 2 screws

6)  Carefully remove back plate.  REMEMBER THE SPRINGS!!!!

7)   Remove the tumblers and watch the springs!

8)   Arrange the tumblers to fit your key

9)  Put the tumblers back into the lock ONE AT A TIME.

10)  Test your key.

11)  Reverse steps 1-6 and enjoy your new lock.

12)  Repeat steps 1-11 on your other lock.

NEEDED:  I'm missing  this piece if anyone has it.
You can see it's missing  here .