As I didn't want to do any modifications to the fader plug itself, I soldered toghether an adapter plug, assuming that there are no other components on the small "connector board" in the original image above (see my first post).
I made it such that it plugs into the J16 socket, as stated on the innofader website. This way the fader worked perfectly and the mixer didnt explode/fry/incinerate either.
Another problem arose when I tried to mount the innofader into the mixer. I had to lift it up about 5-6mm in order to have the shaft stick out of the face plate. The washers and screws in the innofader package were not sufficent to achieve this and I had to buy extra parts from the hardware store. Additionally I had to file down the bottom of the plastic fader knob about 1mm so it wouldn't get stuck on the face plate surface.
As for the room for the connector boards, they barely fit underneath the innofader. Instead of utilising the shrink wrap, I wrapped them as tight as possible into electrical tape to have them take up as little room as possible.