[SR-Users] How to print out all variables in case we reach this line?

[gh]

If i call a mobil number:
t: <sip:+4917625251111 at sip.heissa.de>.

i get 404, but would expect rewrite to carrier route: 
sip:+4917625251111 at sip.nexxtmobile.de
Is there a way to print out all variables at this moment?

###########################################################
   if ( is_method("ACK") ) {
                 if ( t_check_trans() ) {
                         # no loose-route, but stateful ACK;
                         # must be an ACK after a 487
                         # or e.g. 404 from upstream server
                            route(RELAY);
                         exit;
                    } else {
                            # ACK without matching transaction ... 
ignore and discard
                         exit;
                 }
            }
         sl_send_reply("404", "Not here");
         #How to print out all variables in case we reach this line???
         exit;
###########################################################