asterisk users - Sep 2009 - Problem with NAT settings?: SIP reply CALL-ID from ITSP has internal address in host part

We are using using what Cisco's Port Address Translation, so that all
SIP traffic is done through %EXTERNIP%. ?To any outside box, it should
look like the asterisk server is actually on %EXTERNIP%.

My SIP packet gets sent to the ITSP with a Call-ID:
2fd557964ca936b66661d72f1328c918@%EXTERNIP% , but the SIP 200 OK reply
from ITSP has Call-ID: 2fd557964ca936b66661d72f1328c918@%INTERNIP%.  I
can not figure out where the ITSP is even getting my %INTERNIP% from,
I don't see if in the packet anywhere.

I have externip, localnet, and nat=yes all setup in my sip.conf.  Any
ideas of where to look for the source of this problem?


-aws