Wenn man in TYPO3 die Seiteneigenschaften um den Typ Datei/PDF erweitern will...

extTables.php

<?php
/**
 * Overriding $TCA
 *
 * The TYPO3 Configuration Array (TCA) is defined by the distributed tables.php and ext_tables.php files.
 * If you want to extend and/or modify its content, you can do so with scripts like this.
 * Or BETTER yet - with extensions like those found in the typo3conf/ext/ or typo3/ext/ folder.
 * Extensions are movable to other TYPO3 installations and provides a much better division between things! Use them!
 *
 * Information on how to set up tables is found in the document "Inside TYPO3" available as a PDF from where you downloaded TYPO3.
 *
 * Usage:
 * Just put this file to the location typo3conf/extTables.php and add this line to your typo3conf/localconf.php:
 * $typo_db_extTableDef_script = 'extTables.php';
 */

// Rotate loginbox images from this directory
# $GLOBALS['TBE_STYLES']['loginBoxImage_rotationFolder'] = '../fileadmin/loginimg/';

// Raise upload limit for images in 'image' content-elements to 10*1024 bytes = 1MB
# $GLOBALS['TCA']['tt_content']['columns']['image']['config']['max_size'] = 10*1024;

$GLOBALS['TCA']['pages']['columns']['urltype']['config']['items']['5']['0'] = 'file://';
$GLOBALS['TCA']['pages']['columns']['urltype']['config']['items']['5']['1'] = 5;
$GLOBALS['TCA']['pages']['columns']['url_scheme']['config']['items']['3']['0'] = 'file://';
$GLOBALS['TCA']['pages']['columns']['url_scheme']['config']['items']['3']['1'] = 5;

$GLOBALS['TCA']['pages']['columns']['url']=array('config' => array
  (
  'type' => 'input',
  'size' => '15',
  'max' => '255',
  'checkbox' => '',
  'eval' => 'trim',
  'wizards' => array
      (
      '_PADDING' => 2,
      'link' => Array
          (
          'type' => 'popup',
          'title' => 'Link',
          'icon' => 'link_popup.gif',
          'script' => 'browse_links.php?mode=wizard',
          'JSopenParams' => 'height=300,width=500,status=0,menubar=0,scrollbars=1',
          ),
      ),
  ));
?>