Well done Rob.
It's possible the Civile regulator is different?
A lot of the Civile came with Dynastart as standard, so maybe they used the same reg. for all?
I'm afraid it's well outside my scope of experience.
Would be good if you could post up details of the pulley. I know others have had problems sourcing one, and some are living with the stock one, and only charging at high rpm.
Good luck, and hope it all goes well