There are quite a few fixes for that problem. I took all the trim off on my blue wagon, peeled off the plastic and then sanded. I then painted a basecoat of light brown and then spotted it with a dark brown. It came out real good. I think I did it 5 years ago.
Some other guys, remove and then buff it, to it's stainless color.
I think if I were you, being in Norway, I would do it on the car. The reason, if one of the clips breaks, it's a little bit of a problem getting the replacement in Norway.
Check out this site for wagons:
http://gmlongroof.4umer.com/forum.htm
In fact there is a guy, Ian "1a1wind", who has just done that, on the car. I saw it, and it looks good. PM him and he will help you out.
Actually, he is the "Wagon of the Month" on that site. Check him out under the LROM heading.
Good Luck
Tom C.