use P-Asserted-Identity or From-User

kamailio/auth.cfg

@@ -81,9 +81,11 @@ route[SETUP_AUTH_HEADERS]
        $xavp(hf[0]=>X-AUTH-Token) = $avp(trusted_x_header);
        $xavp(hf[0]=>X-AUTH-URI-User) = $rU;
        $xavp(hf[0]=>X-AUTH-URI-Realm) = $rd;
-       $xavp(hf[0]=>X-AUTH-To-IP) = $RAi;
-       $xavp(hf[0]=>X-AUTH-To-Port) = $RAp;
-       $xavp(hf[0]=>X-AUTH-Source) = "trusted";
+       if($ai != $null) {
+            $xavp(hf[0]=>X-AUTH-From-User) = $(ai{uri.user});
+       } else {
+            $xavp(hf[0]=>X-AUTH-From-User) = $fU;
+       }
        return;
    }