I am trying to proxy a request from server A to server C with me being server B.  i send the invite from A to B, then i need to send to server R which returns back to me a 300 redirect, which i then need to take the answer from the Contsct and then proxy the original invite from A to C.  server A can not handle 3xx responses and must be proxied.  I havent been able to find any examples where the 300 is intercepted and a new invite to the target is sent.  i have the following code but it results in no new INVITE and the original session is hung until it is canceled.    Any idea what i may be doing wrong?  In the example below i am just hardcoding the uri for the new invite instead of getting from the Contact as a debug exercise.  I am using Kamailio 5.7.3

route[HANDLEREDIRECT] {

      msg_apply_changes();

    xlog("L_INFO","DBG: redirect headers  [$var(test)]: from=[$fu] from_user=[$fU], to=[$tu] to_user=[$tU]");

      # send to gateway

    $var(new_uri) = "sip:" + $tU + "@" + "gateway";

    if ($var(new_uri) != "") {

        $ru = $var(new_uri);

   $tu = $ru;

     record_route();

  route(RELAY);

     exit;

# i have also tried using 

   #t_newtran();

# and

   #t_relay();

}

    xlog("L_INFO", "DBG: manage reply");

    if (t_check_status("3[0-9][0-9]")) {

        xlog("L_INFO", "DBG: got 3xx redirect");

I also tried using uac_redirect module, but it stalls the incoming invite also, and i cant figure out how to modify the uri from the contact before sending (to add params)

failure_route[MANAGE_FAILURE] {

     if (t_check_status("3[0-9][0-9]")) {

       get_redirects("3:1");

       t_relay();

     }

}