I am trying to accomplish the following:

Asterisk PABX (192.168.10.189) ==> Kamailio(xxx.xxx.xxx.xxx) ==> Cisco PGW 2200 (PSTN gateway) (yyy.yyy.yyy.yyy) ==> Kamailio(xxx.xxx.xxx.xxx) ==> Asterisk PABX (192.168.10.189)

When trying the above scenario, the call is silent and drops after a few seconds. In syslog i observe the following error:

ERROR: <core> [parser/parse_rr.c:84]: parse_rr(): Error while parsing name-addr (sip:22030305@192.168.10.189:5060>)

Looking at the sip trace i see that his might be caused by the ACK message received from the ASTERISK PABX? :

ACK sip:22030305@192.168.10.189:5060 SIP/2.0
Via: SIP/2.0/UDP 192.168.10.189:5060;branch=z9hG4bK3c80f516;rport
Route: <sip:xxx.xxx.xxx.xxx;lr=on;ftag=as166b1eea;did=97b.66623da5>,<sip:22030305@ yyy.yyy.yyy.yyy;pgw-call=call-55bc4>,<sip:xxx.xxx.xxx.xxx;lr=on;ftag=as166b1eea>
Max-Forwards: 70
From: "22498045" <sip:22498045@192.168.10.189>;tag=as166b1eea
To: <sip:22030305@xxx.xxx.xxx.xxx>;tag=as6d578713
Contact: <sip:22498045@192.168.10.189:5060>
Call-ID: 5e2d61160bd1bec9214e2d7d04e5a778@192.168.10.189:5060
CSeq: 102 ACK
User-Agent: FPBX-2.8.1(1.8.12.0)
Content-Length: 0

After contacting Cisco they informed us that issue is cause by B2BUA from our current version of Cisco PGW 2200 that doesn't support this feature. Is there a module, solution that i can implement on Kamailio that could temporarily resolve this issue?

Thanking you in advance.