[mkgmap-dev] Mapsource

Hi, I try to get a map I made with mkgmap to work with mapsource. I split the gmapsupp.img using wgmaptool (gmt.exe -S -f 1331 gmapsupp.img). When I run install.bat it says that mapset00.img is missing. Then I copied the 63240000.img created by mkgmap into the directory, renamed it mapset00.img and everything works. Should mkgmap include the overview map mapset00.img in the gmapsupp.img?