Thanks for your reply.
Your advise has the advantage to avoid license costs for every mobile device. In my case, all mobile devices are on cars which may never or seldom reach the office and have to communicate over a mobile phone line. So sending maps to them can be slow and expensive. Additionally the drivers need the possibility to use a navigation system. They should get the most of his travel targets from the office (maybe as geocoordinates), pick this targets from a list and add some targets on the fly, route or calculate optimal routes and have navigation support (GPS integration). Maybe they should get route recommendations from the office.

Thanks again

Chris Werner