How do I install this part?
http://catalog.peachparts.com/ShopByVehicle.epc?q=1981-Mercedes--benz-300sd-Body--Mechanical--Trim&yearid=1981%40%401981&makeid=63%40%40MERCEDES%2DBENZ%40%4063%40%40MERCEDES%2DBENZ%40%40X&modelid=6205%3AMBC%7C1510%3AED%7C10000134%40%40300SD&catid=241766%40%40Body+Mechanical+%26+Trim&subcatid=242923@@Window+Regulator+Roller&mode=PA

It is missing so the regulator is not attached to the window.
I do not see any way to attatch it to the arm.

__________________
83 300SD Dark Silver Dark brown inside