Ah, good to see the other pictures are not lost!
This is getting slightly off-topic, but I think it might even be possible to use this method with a Slotket that has holes in the PCB (like the ASUS S370-DL) and a simple, custom-made retention plate from, let's say, 5mm aluminium. You would only need to make a big enough plate, add one cutout that fits the cooling plate of the Zalman and four threads to match the holes in the PCB. Then you could carefully (!) attach the cooling plate to the CPU and proceed with assembling the cooler. However you would still need to come up with a solution for the "backplate" part of the Zalman cooler, probably a second, thinner retention plate that would use the same four holes and hold the Zalman backplate in place so the heatpipes and actual cooler can be mounted to it. If you are absolutely aiming for a passively cooled Slotket solution, it might be worth the effort.