Victo, maybe I am missing something here, but if you hold a JAA Comm, once the FAA verification process is done, you will have a FAA PPL based on your JAA certificate. You then wish to do an FAA type rating. If you do the FAA Comm written, and maybe the IR and the type rating, which is done to FAA ATP standards, then you should end up with a FAA Commercial certificate, and therefore have the legal right to work on that type as long as it is N Reg, or you obtain a validation for M, VP etc. There is no reason why you cannot "raise" the FAA certificate to match the one you already hold from a foreign country by doing a type rating. Then, if you meet the requirements at your next recurrent, upgrade to the ATP.
I agree with 500 Above, Your certificate will say "based on," but it will also say US Test passed.
Last edited by B200Drvr; 30th Dec 2012 at 22:54.