corsa b clocks

[supergm]

hi there, im in the closing stages of my build and have just purchased some clocks with a rev counter in which are out of a later spec corsa, now comes my problem, my car is an n reg 1.2 8v with cable clocks, ive changed the engine for the x16xe out of an astra but kept the original 8v gearbox, the astra gearbox came with an electronic sensor in, is there anyway i could use the two together to make my clocks work, or do i have to do as it says in the guide in faq, also im using megasquirt management would this effect it in anyway as i dont know if the clocks use the ecu,
cheers james