Yup, theres a narrow part between the flywheel and the gearbox IIRC there is a plate with 3 tiny cheesehead screws and a little plate, the cable is pushed into this hole and held with these. You should be able to get at it through lifting the centre panel of the seatbox.
The screws are a pig to put back in once out, and the whole job is a bit of a fiddle, if yours is anything like mine, you will be working in a recess, through a 1/2 inch thick layer of black compacted oily goo.
Having a magnet handy might be advisable i recon.
Hope that helps Dan