Filippo,
I've writed a hotplug.d script that readd interfaces that are present in every bat definition of batman-adv uci file when network restart or an interface come up. This script must be placed in /etc/hotplug.d/net/
P.S. for Marek you don't need to split /etc/init.d/batman-adv function in a separate file such the previous emails.
I am little bit late with your script but finally got around looking at it. Why don't we use the functions from /lib/batman-adv/config.sh as we previously discussed ? Any unexpected side effects ?
Regards, Marek