[OpenSER-Users] Saving public IP in CDR

Hi, I'm trying to do add accounting to our OpenSER server. Getting accounting to work is easy but I'm having trouble saving client IP addresses with every CDR. Most of our SIP UAs are behind some form of NAT and to "prove" that calls have originated at the client I want to save the public IP address and as extra service also the private IP address of the UA. Saving the private IP address is easy, $Ri contains this value. I'm having trouble finding out what to do to save the public IP address. I thought that since I'm using fix_contact() I could save the contact header body, but $ct still contained the private IP address. Is this even possible? -- Andreas Sikkema