How to manipulate NAS-Port-ID from freeswitch using libfreeradius v1.1.7 ?

Hello, All! I`ve a problem :( I must interoperate with PortaBilling Radius server, which requires from me to send 5060 in NAS-Port-Id attribute. I can`t understood, how can I do this. It always equal to zero. I found that I must write something to /etc/freeradius/port-id-map, but I don`t know what port freeswitch using (eg /dev/tty0) Help me, please!