mailcheck does not have support to check imap/imapssl servers.
i don't know if this would help, but, gnome's mailcheck applet deals with imap. I think most of the functions dealing with imap connections are in popcheck.c http://cvs.gnome.org/viewcvs/gnome-applets/mailcheck/?hideattic=0
Ok, setting this to WONTFIX. Work is underway for a new mailwatch plugin with this functionality.