I want retransmit some me ssages to other sip server as is. f.e server sip1.com receives invite message INVITE user@somewhere.org

i want to send it to server sip2.com as is. Unfortunately, if i use rewritehostport() function, or modify $rp $rd pseudovariables fe $rp='sip2.com', kamailio changes invite uri, and send to sip2.com INVITE user@sip2.com The To: filed left untouched

How can I resend message without modifications? I've tried also modify $dp and $dd pseudovariables, but then message wasn't sent anywhere,and in log I can see this message:

Jul 27 15:44:54 dsdb01 /usr/sbin/kamailio[17786]: ERROR: tm [t_fwd.c:1523]: ERROR: t_forward_nonack: no branches for forwarding Jul 27 15:44:54 dsdb01 /usr/sbin/kamailio[17786]: ERROR: tm [tm.c:1375]: ERROR: w_t_relay_to: t_relay_to failed

What else can I try?