Garming GPS dowload Maps to SD instead of device

Create folder \Garmin on the SD card.
Copy the file garmindevice.xml from \Garmin folder of your device into the \Garmin folder of the SD card.
Run the Garming express , it should detect the SD card as a Garming GPS.

The map files will end up on the SD card in folder \.system and will be named gmapprom.img, gmapprom.unl and gmapprom.gma. Create folder \Map on the SD card and move these three files into it. You can then rename the files from gmapprom to any name of your choosing, but keep the .img, .unl and .gma extensions.

If your device has junction views, you will find a JCV folder within the \.system folder on the SD card. Move the JCV folder and its contents into the \Garmin folder of the SD card.

Full details in http://www.poi-factory.com/node/39231