change button id

configureproductdomain.tpl

@@ -130,7 +130,7 @@
                                         </div>
                                     </div>
                                     <div class="col-sm-2">
-                                        <button type="submit" class="btn btn-primary btn-block" id="useOwnDomain">
+                                        <button type="submit" class="btn btn-primary btn-block" id="b_existing_domain">
                                             {$LANG.orderForm.use}
                                         </button>
                                     </div>