I'm 99.9% with bose-x and Julian on these comments.
As an aside, the .1% that I don't agree with is that there is not a 2 hour solo requirement for night qualification training under JAA.
I would agree that the average FAA instructor - and even FAA employed inspector - wouldn't know how to read a JAA licence or be able to check compliance with currency requirements.
I'd also agree that, unless your JAA licence has night qualification attached, you have no night privileges with your 61.75 licence "issued on the basis of" - even if you attached an instrument rating
"US test passed".
Don't forget that a lot of advanced ratings and qualifications are based on the assumption that you must already hold certain qualifications before you apply for others - so you couldn't have attained "B" unless you already had "A", therefore if someone was applying for "C" based on the fact that they had "B" (but had never qualified for "A") it opens up a complete can of worms.
Let say, fictional scenario: "A" is vanilla ICAO PPL (no night), gets "B", FAA PPL issued on the basis of, applies for "C", FAA instrument, based on the assumption that he holds an FAA PPL ("B"). If the night was a prerequisite of the FAA in order to be allowed to sit the I/R check ride then they would not qualify - which, having just re-read bose's last post, is exactly what he just said.
I rejected an ICAO licensed applicant for a UK CAA flight test a couple of years ago, based on the discovery that he had not completed training sufficient to qualify for the issue of a JAA night qualification. UK authorities came back and said that anyone holding an instrument rating was night authorised - but I pointed out that that authorisation was based on the assumption that a night qualification was a prerequisite of being able to attend the training course for the UK instrument rating.