I use /etc/vz/conf/veid.mount and .umount files to control container-specific iptables and routing on HN. Thus I don't have to modify startup configs on various HNs, everything is packed with container. Old vzdump does back up these files, vzpbackup does not.
Please, please, please! fix that. Currently vzpbackup backs up veid.conf file only... I still can't move my containers to ploop without this feature :(