Hi this may be a totally stupid question but I am changing over from 6700 to 6800. I can see as opposed to being placed on the underside of the shifter the gear shift mechanism is now on the outside of the shifter. I have threaded the gear cable into the slots provided, lifting the dustcover plate and using the slots on the shifters, however now that the cables are in the levers are not shifting the cable whatsoever, where have I gone wrong here?