You can build angle brackets that attach to the slots on the back of the fence extrusion and hold it down that way. You could make the backets out of steel or aluminum angle but it needs to be at least 1 1/2" wide for stability I would think. What you don't have is a cutout in the fence where the router bit will be turning. Another pair of extrusions mounted to the front side of the fence with mdf faces added would give you that.
Someone I consider a master woodworker once told me that a master woodworker is not someone who never makes mistakes. He is someone who is able to cover them up so that no one can tell.