What you want is the "badge board" bootloader source code.
At this years FTF they had a badge with a JM60 on it that you could program. When you connected the badge board to a USB part it came up as a hard drive and you could drop an s19 file on it for it to program.
You can get the source code from "canyourbadgedothis.com". You have to register then click "Contest Tools" and down load the Boot Loader zip file,. You will need CW 6.2 to build it.
I have not looked at yet, so tell us how it works out.