Does anyone know how to fit the trigger sensor assembly on a distributor for the s2?

I have got the distributor off, cleaned etc, but cannot find a way tu pull or remove the main spindle from the distributor body. There does look to be a key way at the base of the distributor that joins the cam shaft, but am reluctant to hammer this out as this may harm it or cause damage. Also I know that the top end of the distributor that breaks the beam, a rotor, is very fragile and I am very relucant to damage this also as it is very thin.

Anyone any ideas or suggestions?

Cheers.

Peteb, Essex