I think i can help you Carsten :)
When I tried to take it off her, she started crying, and only stopped when I put it back on her head.. So now I have a problem to solve, since she is definately not gonna sleep with it on !
Ok heres what you do.... you let her go to sleep with it on... and then gently take it off.... veeeeeeery gently lol 
im sure you've already fixed your problem but i figured i'd try at least lol