I'm looking for the possibility to get SIP response string from B leg, do some transformations and pass it back to the A leg.

Example response from B leg:

SIP/2.0 500 Trunk Prefix Mismatch

When FS receives that response from B, it ignores text message "Trunk Prefix Mismatch" and send to the A leg reply with it's own message SIP/2.0 500 Internal Server Error

How to get that response or pass it unchanged to the A leg?

Best Regards