Trailer-numberplate

In Holland, you have to stick a numberplate onto your trailer with the same numbers as on the car, if this trailer is below 750kg (max ballast).
For a year now, these plates have to be white and have to meet all kinds of standards, so a carton-plate is not allowed anymore.
Because I had to travel with a (rented) trailer from Groningen to the south of Belgium and back (950+ km) (to help the girlfriend of my friend move to Groningen), I had to get one of these too.