You're lucky your ball joints popped out easily, usally this is the problem end. To get to the 22mm end, use an open end or box end wrench to hold the nut, while using a socket to turn the bolt end. BMW recommends to replace all the 22mm self locking nuts. Remember to lower the car to the floor or on ramps before you torque down the arms to the frame. Otherwise the bushings will wear prematurely.