This thread is a bit old and you probably solved it or dumped it but I came up with a similar problem after the second rubber mount failed on my Vendetta 2 which left the fan unsteady and away from the heatsink. I solved it using a long machine screw and nut of about 3.5mm in diameter. It was a screw which was meant to secure an electrical plug/switch faceplate to the wall metal backbox inside the wall.
I do intend getting some more of the screws and nuts with a few rubber washers in order to provide the vibration absorption. They do squeeze between the heatsink aluminium plates into the cutout where the rubber fixing used to be inserted. It's working okay ATM. The screws need to be fairly long at about 40 to 45mm, 45 to be certain if fitting a rubber washer and then push the fan onto the screws and tighten with a nut. It works better than those horrible rubber mounts which are a pain to fit or remove.