Thank You for your answer Downunder.
But I tried already 7.9xx and 8.0xx versions with no luck (I have some different CE-versions a long time on my PC).
I think the 7.451 version is the limit for my Dell/Windows CE combination. I am satisfied with it. I always come by my destination, even without Lane Assist and Speech etc.
Just put a 895.4444 map on the sd-card. TTNavigator still works with this new edition. (and for backup I have always my Garmin-outdoor gps with the latest City Navigator).