I believe this is how Kris is doing it:

1) Use NavTweak to save out to file the language modules that you are going to switch/exchange from the NavBoot file (e.g. if you want to exchange all of the English language strings for the American language strings then you would save out the "Lan_American" module).

2) Use a hex editor program such as HHD Software Free Hex Editor to change the module name at position 0x00000058 (e.g. change the module name in the saved Lan_American module file from "Lan_American" to "Lan_English").

3) Use the hex editor program to change the two language related strings at around position 0x000000ed0 (e.g. change "USA" to "GB" and change "US Eng." to "English").

4) Use CRC-24.exe to correct the CRC info of the language module file you've just modified/changed (apparently the CRC-24.exe program can be found in the HackTheIBus yahoo group). The CRC is the last 3 hex numbers in the file (XX XX XX).

5) Import the modified/changed language module back into the NavBoot file using NavTweak and save it.

I hope this helps some.

-- MIKE