[Users] route on reply reason in failure_route

Can anyone please give me a hint how to access the reply reason in failure_route - or is it really not possible to trigger some event on the response _reason_. 0(704) SIP Reply (status): 0(704) version: <SIP/2.0> 0(704) status: <404> 0(704) reason: <CLIR Inactive> <----- I want this! There is a pseudo variable for that, but no function can search the replied reason! Is it really true, that you can use the reply status only (t_check_status("404"))? Using avpops the pseude variables $rr and $rs are <null> at that moment. Do I miss something? I'm doing that: failure_route[3] { if (t_check_status("404") ) { avp_printf("$reason", "The reply: $rr, $rs"); log("\n----------------------------------------\n"); avp_print(); log("\n----------------------------------------\n"); } } resulting in: 0(740) DEBUG:avpops:print_avp: p=0xb6177838, flags=2 0(740) DEBUG: id=<32> 0(740) DEBUG: val_str=<The reply: <null>, <null>> Any hints welcome. /Walter