asterisk users - Sep 2003 - Extract header(s) of SIP signalling messages

googled: yes, asked #asterisk: yes..

I need to extract headers of the SIP call signalling protocol on 
outbound calls (especially call setup response message/ 200 OK).

Example:

phone with extension 33 place a call to the number 12345 (or 
sip:12345@anyproxy.dot.net:5060) via SIP. The SIP proxy then sends a 
header within a call setup response which is important for further CDR 
processing.


I appreciate any idea.


Michael