iSync for non-current user

[jsruok]

I have set up a cron job to iSync regularily. However, sync won't take place if user is not logged in or if some other user is active (using window manager). ("INIT_Processeses(), could not establish the default connection to the WindowServer.")

Is it possible to perform iSync on user that has not logged in?
Or, can one iSync if user has logged in, but is not the current user that is using window manager?