Warrior, you dont need to convert you JAA PPL to an FAA PPL to enable you to continue. You can go straight into the IR.
Mate and myself also did our in CA last year but at Rainbow Air in Longbeach. Mate also stayed out there and did his multi IR which apprently was combined with the multi checkride, consisted on flying a hold and a couple of approaches, I beieve one with an engine out.
Regards,
Julian.