Putting the unlocked gmap in the Mapsource/Maps directory won't work.
You must put the gmaps in (different for the windows-version):

- Windows XP: C:\Documents and Settings\All Users\Application Data\Garmin\Maps or C:\Documents and Settings\{username}\Application Data\Garmin\Maps
- Vista/Windows 7: C:\ProgramData\GARMIN\Maps or C:\Users\{username}\AppData\Roaming\GARMIN\Maps (also Windows 8 I guess)