I have KMZ map files loaded onto a microSD inserted into my 760i. What next? How do I access the maps? Note that I cannot load maps from my computer because it is a Mac running the latest OS and it refuses to acknowledge that my Garmin exists as a drive when connected by cable, despite Garmin Express being able to update software etc etc. (I have followed all the instructions in the manual about connecting to the computer, and followed all the troubleshooting tips.)