tume,
I am not a lawyer, but I would suggest the situation is that you have logged time as required by FAA, that should be entered in the new log book as is, then carefully write an explanation as to the numbers and draw a line under it.
Read the FAA regulations very carefully about what counts as command time in a log book, and get that right. Nobody can require you to change legally logged hours in retrospect.
Then start your new EASA entries.
Last time I looked, UK CAA recognised a "co-pilot" as pilot flying as P1U/S, In Command Under Supervision, but JAA/EASA may well have screwed that up. See CAA CAP 804, S.1, Part E.
Last edited by LeadSled; 30th Apr 2015 at 15:29.