My bad, Amendments 5 and 3 are indeed in use. Concerning the "conversion" of the type or as you properly said the "transfer", that requirements seems to me relevant since it is a matter of hours on type amongst other requirements. The reference should actually be done to JAR–FCL 1.240 (a) (5):
(5) At the discretion of the Authority,
an aeroplane class or type rating may be
issued to an applicant who meets the
requirements for that rating of a non-JAA
State, provided JAR–FCL 1.250, 1.255 or
1.260 as applicable, are met. Such a rating
will be restricted to aeroplanes registered in
that non-JAA State, or operated by an
operator of that non-JAA State. The
restriction may be removed when the holder
has completed at least 500 hours of flight as
a pilot on the type/class and complied with
the revalidation requirements of JAR–FCL
1.245, and if applicable JAR-FCL 1.251