I tried to translate the welcome message from the installed rooms 'lobby' and 'friends' directly in the database.
That doesn't work, I mean ... it doesn't show on my website.
Than I deleted those 2 rooms from the database, but they still show on my website.
I created a new 'Lobby' with a new welcome message (in dutch) and that room shows on my website.
So there obviously is a problem with managing chat rooms.