I have put some extra routes on a 2GB SD card for an up coming trip using a card reader. When I put the card into the Zumo I can't work out how to read the routes. When I look at the card on the computor the routes are on there I also wish to take a copy of all the routes for the trip incase the Zumo throws a fit and losses them, so I need to be able to read and use the routes onthe card. What am I not doing