You can easily exceed 2025 limit using "GmapTool v0.21". This program helps join different *.img files generated by Mapsource.
Collect all *.img files with 2025 limit, generated by Mapsource in one folder (must have different names). Insert to folder gmaptool program. In windows command shell execute sth like this:
gmaptool -jo gmapsupp.img *.img
Copy gmapsupp.img to "Garmin" folder in your SD card of your GPS.
Program can be downloaded from (the manual in english is included inside zip folder):
http://www.anpo.republika.pl/files/gmaptool021.zip
cheers! a.