Rear bumper sag

[Columbo]

Hi All,

I've had my '97 323tiA rear bumper sagging a bit for some time. It's not much, but I've seen better:





(Sorry for the low quality photos and dirty car. The weather is awful in southern Finland!)

Now when I had time I tried searching from google and various forums for the instructions to fix it but I didn't find anything specific. From what I've understood there are supports right behind the rear wheels which may need adjusting or replacing. The part I'm talking about is part 5 in the picture below: (part 5, P/N's 51 12 8 146 095 and 51 12 8 146 096)



Do I have to remove the bumper to access these supports? And where are the supports attached to the body of the car - how can I access there and how can I adjust/replace them?