Assuming you have a JAA Licence the details of how you log the time are in
JAR-FCL
WRT Whopity he's wrong
(2) Co-pilot flight time
The holder of a pilot licence occupying a
pilot seat as co-pilot may log all flight time as
co-pilot flight time on an aeroplane on which
more than one pilot is required under the type
certification of the aeroplane, or the
regulations under which the flight is
conducted.