Tryed to post this earlyer today, had problems wit the connection.
This is the DIY bracket i have used on the white folder (der, not hubgear) for several years. I doubt that your chainstays are "fat" enough to use this system plus the arm of the coaster brake is where you want this thing to be.
DIY trailerhitch 3
DIY trailerhitch 2
DIY trailerhitch 1