[SR-Users] Inserting a message into a transaction?

[Daniel Tryba]

For a retarded endpoint (an old ISDN PBX behind a Smartnode) I need to
insert a 180 reply before sending a 183 (with SDP), otherwise the PBX
fails to playback the inband audio to the caller behind the PBX.

I can't find hints on how to do this. uac_req_send() can be used to
start a new transaction, but I only need to generate a 180 based on the
183 in the on_reply route.

Current Q&D hack is to send a 180 on the initial INVITE, works but not
ideal.