Go in and delete the service book for BBMaps. Then remove them completely from the applications list on DM. "highlight, and click delete".
Reboot the device. Connect to DM, and re-install from the downloaded copy..
This method worked for me. The newer version of maps that comes with 4.5, has to be servicebook controlled. And the older version does not. When you remove both from the DM's install list, and replace it with the downloaded version, it should make it show up. Good luck...