You can do CPL subjects in JAA land but you'll also have to do the IR subjects. For some strange reason the sum of those 2 topics is greater than the 14 JAA ATPL exams.
Note, the exams do lapse if you don't keep your IR current etc.
Until you have the hours and pass an LST, you still have a CPL.
In Oz (and other countries), you do your CPL subjects for the CPL and the ATPL subjects for the ATPL. Irex paper for the instrument rating.