I haven't tried this with WinCE 6 but it might work.
1. Download my program from http://www.navitotal.com/showthread.php?1274-Garmin-Mobile-XT-for-WinCE5.0-program
2. Using Winrar, extract the folder to your SD card.
2a. Start the program.
3. Choose "connect to a Garmin device."
4. "Skip" scanning attached.
5. Choose yes to skip.
6. Choose I agree.
7. Choose no to connect to other Garmin devices.
8. Click arrow on lower left.
9. Click "wrench icon" - tools.
10. Click settings.
11. Scroll down to "about."
12. Write down "card id" number.
13. That is the number you use in the JM Keygen to create the SW.UNL.
14. Using a blank "notepad" page, copy the number created by the keygen.
15. Name it SW.UNL and save it as "all files" NOT ".txt."
16. Copy the newly created SW.UNL file to the Garmin folder on your SD card.
17. Shutdown your device, wait a few seconds and restart.
18. When you next start your Mobile XT, it should now go to accepting the license immediately without seeing the four options.
19. You should use the unlocked .img maps for your device. Even though I use the unlocked .img files on my device, I still created an unlock for them using the keygen. Maps for the SD card are gmapsupp and for the internal device flash drive they are gmapprom.