After installed the mod with iptables and thank you to pfeffer now you can use the FBF with messagenet.it.
This is the command.
iptables -t nat -A OUTPUT -p udp -d 212.97.59.76 --destination-port 5060 -j DNAT --to-destination 212.97.59.76:5061
This is the command.
iptables -t nat -A OUTPUT -p udp -d 212.97.59.76 --destination-port 5060 -j DNAT --to-destination 212.97.59.76:5061