Is there an option in sophia profile for external sip port?

Hello.
My freeswitch setup is behind firewall. The firewall have two public IP with different providers. The rules of firewall is made with sticky sessions. I would like to have internal and external profiles accesible on both public IP. So far I thought about creating internal and external sofia profiles for each public IP which will listen on same local ip of the server but on different sip-ports. Unfortunnaly this does not work. Clients cant authenticate.

Sofia profile have sip-ip and ext-sip-ip for this, but seems that ext-sip-port does not work as loading profile failes with invalid ext-sip-ip:ext-sip-port combination.

Or is there another option to specify external IP si port (which I want to provide to clients) different from local binded sip-port?

There is also ext-rtp-ip that can be set. freeswitch/conf/vanilla/sip_profiles/internal.xml at master · signalwire/freeswitch · GitHub Check here for more information Sofia Configuration Files | FreeSWITCH Documentation

the problem is not with rtp audio, but with sip. Sip conversation is not accesible on different port from external