I have a Bernina walking foot also. Mine came with 2 different metal bases. One is like the one on yours and it also came with one like the one that you are describing that has a metal bar across the front. When I put my walking foot on it does take some work. I have to turn the front of the foot toward the right a little bit as I am getting on the shank so that I can get the bar to go around the screw also. As i am lining up with the screw I twist back to center. I hope this helps you.