To have kamailio start at boot time, you have to adapt
${SYSCONFDIR}/kamailio/kamailio.cfg and insert the following
into /etc/rc.local.

if [ -x ${PREFIX}/sbin/kamctl ]; then
        install -d -o _kamailio /var/run/kamailio
        echo -n ' kamailio';   ${PREFIX}/sbin/kamctl start
fi
