/**
 * if you have a matrix, you'll need to add this after your form
 */
<script type="text/javascript">
$("table.matrix tbody tr :input").each(function() {
  var i = $(this).parents("tr").index();
  if (this.name.match(/row_order/) && this.value.match(/^row_id_\d+$/)) {
    this.value = "row_new_"+i;
  } else {
    this.name = this.name.replace(/row_id_\d+/g, "row_new_"+i);
  }
});
</script>