I have been flying for the last four years on a validation based on my Australian ATPL. I completed TRI/SFI training with Boeing Gatwick after talking advice from CASA but have since been rail roaded. CASA seem happy to transfer ratings from an EASA license to an Australian license but not place directly on an Australian license.
I think CASA is correct, ICAO Annex 1 says licence validations cannot be extended beyond the the validity of the supporting licence. So if someone has given you a type rating on a validation, it would not be recognized by ICAO Annex 1 outside the state that issued it.
A validation is not a licence, it is like the international driver permit from the auto club. It is useless without the actual licence.
The process you want to do it a licence conversion in the state you are working, and have the type rating on that licence. CASA would then accept that.
Personnel Licensing FAQ
"A validation cannot provide more privileges than the supporting licence. If additional ratings are required, they need to be added to the supporting licence before they can be taken into account in the validation "
"Additional ratings can be added to the "converted" licence in accordance with the requirements of the State that has converted the licence"
Be careful how you approach this as it may draw unwanted attention to your validation, and you may have that privilege removed.