pnoid,
I suspect that you have an aftermarket cover. Soft tonneau covers are typically dealer installed options and most Sport Trac's do not come from the factory with soft tonneau covers. I suspect that most dealers will have a local truck accessory shop install those kinds of items if the customer requiests it, or the customer may have purchased the tonneau cover after he bought the truck.
If you have a soft cover with an aluminum frame with plastic corners, it may be a Ford cover. I understand that many of those covers had a problem with the plastic corner pieces breaking.
...Rich
