Vario roof right plastic panel broken

Good evening, I have a SL 350 year 2003 in which on the Vario roof outside, on the right plastic cover side of the disc (seen from behind ) when opening the roof below a approximately 10 cm large, almost square piece is broken. Why is even the workshop unclear. One sees a piece of a combi tape. I have the possibility to buy the part individually. Is the exchange easy to accomplish? I would be very pleased about an answer. All MB parts can follow like t to be ordered directly : spare parts select http://www.auto-parts.spb.ru/cat/cats/m.mycat?cat=mb Then enter part number at http://www.online-teile.com/mb/ -} buy greetings from Lake Constance