When I mapped my club sports pedals the sliding bars didn't work but the pedals worked when I tried them out in a race. Had a go at mapping them a second time and the sliding bars worked ok. I'm using the T300rs wheel. All I can say is keep trying.
I had the same problem at first, and this fixed it. Map the pedals just like you would a button for "look left" or "change camera", then go the calibration page and they should work.