This mount will allow you to fit a Diamond Hot End on a ReprapPro version of a Mendel 3. It has an extension to take the modulating probe which is normally fitted to one of the fan mounts. It fits directly on to the existing x carriage mount. If you have the Tri-colour version of he ReprapPro Mendel, then you already have the extruders and electronics in place.
Basically I took the OpenScad file published by RepRap.me (the makers of the diamond hot end) and added the other bits to it. I couldn't quite fathom how the original OpenScad file variables worked (I'm a 62 year old carpenter, not a CAD designer) so I kind of just kept adding bits and playing around with dimensions. It took a few iterations and trial fits but I got there in the end.