You're barking up the wrong tree. Talk to Magellan.
After you try dealing with them you will figure out that they suck and you will want to buy a Garmin. I loved my Magellans until I dealt with them and realized they stink and don't care about handheld units. (I'm not a pro Garmin guy, I have just heard nothing but good things about them.)
I ACTUALLY HAVE A GARMIN GPS ALSO. NOT LONG AFTER I BOUGHT IT I WENT BACK TO A MAGELLAN BECUASE OF THE RECEPTION. THE CHEAP MAGELLAN OUT DOES MANY HIGH PRICED GARMINS. SO I GUESS I WILL STICK TO USING MAPSEND AND LOADING THEM THAT WAY.