Interestingly, I am pretty sure (from both US instructors & reading the relevant FAR part 61 notes) that my FAA PPL issued under Part 61.75 on the basis of my JAR PPL does allow me to fly with passengers at night providing the currency requirements are met.
I'm FAIRLY sure that your 61.75 foreign based certificate only allows you to exercise your existing 'foreign' (ie. JAA) PPL privileges on 'N' reg. aeroplanes.
Thus it WOULD allow night flight you hold a JAA night qualification but wouldn't if you don't.
There are several well documented examples of people getting confused about privileges on a 61.75 certificate.