FAA vs JAA ATPL definition criterias (Modular)

[LPVL]

Dear all,

Speaking about modular:
I would like to know what are the specific criterias that defines a certain ATP license as FAA license, allowing us to work under FAA rules (eg.US) or on the other JAA.

For instance: To have a JAA license should I have to get the Theory and IR in Europe and the remaing modules can be in US?

Thanks in advance.