It depends on your model, and accessory package. Mine has the jack. Some have heat/ac parts, and something else I can't remember. On those, the jack is back in the right rear corner, in view.
Here's a link that shows my custom bracket, at the D pillar base: http://www.fordtransitusaforum.com/...0-project-minimalist-kayak-14.html#post298177
The reply just after that shows an OEM mount, at the rear side wall.