Mapinstall retrieve maps

[persep]

Hi,
I've decide to try Mapinstall patched to install maps to my gps, I normally use mapsource for this. And I've notice a button that says "Retrieve map". I've tried it several times, changing the disk drive and using an usb disk with a img file in a Garmin directory and it always says "the selected device has no maps on it".
So how do you use this retrieve map button?
Thanks

[Kanopus]

Actually it is not retrieving maps but selection list from existing img. Mapinstall can retrieve list of maps, when this img is just like the file created by Mapinstall itself. So this could be for example file \Garmin\gmapsupp.img on removable drive. You need to select this drive as output device on preceding screen.

[persep]

I was trying with the image of the GB dicoverer full and it always said "the selected device has no maps on it" and it was inside a garmin folder

[Kanopus]

This is not a map, that can be created by Mapinstall. Anyway, retrieving maps, that aren't installed on your PC, has no use.

[tammam joha]

even with the mapsorce if you try to import maps along with track and routes points it will require a similar version installed to the mapsorce which mean it only refrence the map not actually importing it