There is a half-moon key on the CAS and the camshaft, which forces the CAS to align correctly when replaced. There is also a set of splines on the CAS and camshaft, that will rotate the CAS if the keys are broken / missing. Check you have the half key in the end of the exhaust camshaft. If not, you have to do some visualising to align the CAS side to where the cam side should be.