As a workaround, and as we don't know if Google will implement imap keywords in near future perhaps could be implemented some trick as this:
A new option --extractgmaillabels1 that will process gmail imap folder structure so as to extract label information. Later label information could be synchronized in destination imap server as imap keywords in a standard way. I supposed it was necessary to look up folders as I did not find label information in message header. imapsync --host1 imap.gmail.com --authmech1 LOGIN --user1 userlogin1 --password1 userpass1 --ssl1 --extractgmaillabels1 --host2 myserver.org--user2 userlogin2 --password2 userpass2 --ssl2 --authmech2 PLAIN --folder '[Gmail]/Todos' --useheader 'Message-Id' --skipsize thanks, txemi.
