Hello,
Any reply code/status translation is going to invoke the absorption of the old reply and the generation of a new one, within the proxy. Proprietary SIP headers would not be conserved in such a scenario.
To add headers to a reply, you can use append_to_reply(), which works in much the same manner as append_hf().
-- Alex
-- Principal, Evariste Systems LLC (www.evaristesys.com)
Sent from my Google Nexus.