Welcome to the board
I don't really know what would be the best place to start looking. Maybe try some junkyards or tuners. Since you're from Germany, you could try to reach intertuning or AVB-sports (links are in the post on top of the forum, in Belgium). You could also try to email a Dutch junkyard specialised in Honda's. You can find their email at their site
www.deijne.nl
Strange, my local Honda dealer always goes out to Germany to find parts for our Begian civics