Can see maps on SD card but not in the GPS unit.

I am a novice at GPS units so bear with me. I purchased a Crossover unit off of ebay a while back and got ripped off. The unit that was sold to me was a EU (European) version. I didn't realize it at first because there wasn't any software sent with it, all I got was the unit itself and some accessories. The SD card has europe roadways on it. After, getting some help I got maps to work in the "hiking" portion of the crossover. This is great because that is what I mainly purchased it for. Although, it would be nice to use it in my car. Anyways, the maps were given to me by a very helpful person off of a forum. Unfortunately, I don't have his email anymore. Well, recently I purchased Map Send USA Topo to see if I could make my own maps. I was able to create a map and download it to my SD card. I can see the map on the SD card, however, when I put the SD card into my crossover it doesn't show up. What is interesting is the maps that were given to me are on the same SD card, so I see all of the maps on the SD card but only the ones that were given to me show up in the crossover unit. By the way the maps all have the same file extension – imi. The only thing I can think that would be causing this is an issue with the serial number. The map send program asks for me to enter a serial number that matches the serial number on my GPS unit. The number on my unit is a 13 digit number, however the map send program only accepts an 11 digit number. If anyone has any ideas I would greatly appreciate any input. Also, since I didn't get any software with my unit does anyone know where I can get the “map tools” software that was supposed to come with the gps unit originally.

Thanks in advance,

Matt