update process

Please, point me to manual about suse update process. We have a set of machines running suse 9.1 and want to have exact copy of ftp.suse.com/pub/suse/i386/update/9.1/ in local dir (local mirror), we are using wget, but it does not remove files absent in mentioned location. Sorry for pretty dumb question, we have no time to google/etc, just help if you can.