When doing a backup to an FTP site I clicked "Cancel" after many files had been moved to the FTP server. When I restarted the backup process the AceBackup 3 program started from the beginning: it copied over existing files that had already been copied to the server. When observing the status of files on the FTP site as AceBackup ran I saw the size of each of the files already on the FTP site reset to 0 and then incrementally grow as AceBackup recopied each file. Obviously, there was no need to recopy files that were already in the FTP backup directory.
How do I get AceBackup to restart the backup from where it left off after clicking Cancel during a backup? In other words, how do I get AceBackup to continue by doing an incremental backup that ignores files that have already been successfully copied to the FTP server and that have not been changed? I want it to be a backup (preserve the file structure of the computer's hard disk) and not an archive.