You need to delete the mobilecache and mapschema from the device and redownload data from the service onto the device - this will pull thru the changes to your domain.
You could try just deleting the mapschema.bin file then next time you fire up the device it will download an new schema file (with the changes in domain)- however you must be connected to the internet (to be able to see the service) otherwise you will get an error message.