You only need an ICAO PPL (FAA) to start your ATPL theory.
That answers my question I was going to ask next, reason for converting the PPL to JAA was to sit the ATPL exams via BGS and then go back out there and convert my CPL and FI and possible employment with Ariben/EFT.
(Seems I don't need to convert after)
After 12 months come home convert the ME-IR to JAA and get an MCC done.
Thanks for your help Davey ... You have a PM coming your way.