Drupal: Remove tax line Item from Order Ubercart

<?php//$Id$/** * @file * Custom Ubercart Tax remove module. * * Allows tax line item to be removed from orders. * @author saru1683 */function custom_uc_add_deleted_lineitem_order_id($line_item_id) {      $sn__order_id = db_query("SELECT order_id FROM {uc_order_line_items} WHERE line_item_id = $line_item_id")->fetchField();    $data = array(    'order_id' => $sn__order_id,  );     drupal_write_record('custom_uc_tax_line_item_deleted', $data);    }function custom_check_deleted_item($order_id) {  $sn__order_id = db_query("SELECT order_id FROM {custom_uc_tax_line_item_deleted} WHERE order_id = $order_id")->fetchField();  if(intval($sn__order_id) > 0)       return TRUE;  else     return FALSE;}function custom_uc_tax_remove_form_alter($form, &$form_state, $form_id) {    if($form_id == 'uc_order_edit_form') {        //_pre($form['line_items']);    }}?>

<?phpfunction uc_order_delete_line_item($id, $order = FALSE) {  if ($order === FALSE) {      if(module_exists('custom_uc_tax_remove'))// add this line for taxes remove       custom_uc_add_deleted_lineitem_order_id($id);// add this line for taxes remove    db_delete('uc_order_line_items')      ->condition('line_item_id', $id)      ->execute();        }  else {    db_delete('uc_order_line_items')      ->condition('order_id', $id)      ->execute();  }  return TRUE;}?>

<?phpfunction uc_order_pane_line_items($op, $order, &$form = NULL, &$form_state = NULL) {  switch ($op) {    ...    ...    case 'edit-form':    ...    ...    foreach ($items as $item) {        if (isset($item['add_list']) && $item['add_list'] === TRUE) {          $options[$item['id']] = check_plain($item['title']);        }                if (isset($item['display_only']) && $item['display_only'] == TRUE) {          $result = $item['callback']('display', $order);          if (is_array($result)) {            foreach ($result as $line) {                if($line['id'] == 'tax' && module_exists('custom_uc_tax_remove') && custom_check_deleted_item($order->order_id))  {// add this line to remove taxes                 //do nothing                } else {// add this line to remove taxes                     $line_items[] = array(                  'line_item_id' => $line['id'],                  'title' => $line['title'],                  'amount' => $line['amount'],                  'weight' => $item['weight'],                );                }// add this line to remove taxes            }          }        }      }    ...        ...}?>

<?phpfunction uc_taxes_uc_order($op, $order, $arg2) {  switch ($op) {    ...    ...     // Now add line items for any remaining new taxes.      if (is_array($line_items)) {          if(module_exists('custom_uc_tax_remove') && custom_check_deleted_item($order->order_id))  {// add this line to remove taxes          } else { // add this line to remove taxes              foreach ($line_items as $line) {                            $order->line_items[] = uc_order_line_item_add($order->order_id, 'tax', $line['title'], $line['amount'], $line['weight'], $line['data']);              $changes[] = t('Added %amount for %title.', array('%amount' => uc_currency_format($line['amount']), '%title' => $line['title']));            }              }// add this line to remove taxes              }     if (count($changes)) {        uc_order_log_changes($order->order_id, $changes);        usort($order->line_items, 'uc_weight_sort');      }    break;  }}?>