Replying to Alpine Trekkers and FKS

So i bought some alpine trekkers for my rossi FKS 140. Is the inserts rear section supposed to hold down the lever that retracts the breaks? In all of the diagrams I see of other bindings that is how it is set up. The problem is the trekker can't become small enough to fit in such a way. The only way it seems to work is on the notch on the heel piece. Is getting rid of the breaks the only way to use the trekker with the FKS? Thanks