Robin, Dee is niet de maker van Den Haag - Schiphol, dus je vraag is hier niet van toepassing.
@Dee Myrone: Which Operating System do you use? I remember that Windows XP indeed had trouble with these German characters, so that could explain something, in Windows 7 all possible characters are installed by default, so that should not be a problem.
I have to say, the last time I looked at this route is about 4 years ago, because the route is really outdated and does not compare to the quality we are used from routes for MSTS by now, so my answer could be a bit off because I had to find it somewhere deep in my memory.
Regards,
Robert