My P&P cage is the same (as was my old SD cage),
it's like a piece of angle iron with the cut-outs where the wing to bukhead bolts go, and then an upside down U shaped bracket thah bolts over the bulkhead outrigger.
Best bet is to remove the wing, then offer up the bracket inside the wing (i'm assuming yours also has t he square plate that sandwhiches the outer wing panel? you'll need to cut this square out of the wing also)
Mine also needed a slight bit of fettling inside the wing... where the top and outer panels meet (and that row of small bolts are) i had to grind away about an inch, maybe half, of the "seam"