Best bet would of been to swap the pump when the engine was out and put a cambelt on it at the same time, just done it with a Peugeot Partner van today. And as Terry mentions, to get at the part thats immobilised on the pump you'll nedd to take a grinder to it and cut the top of the steel 'cap' off it.
*EDIT*
Just realised the age of this thread!.
