RTL css files are not loaded

for multi language sites there RTL css files are not loaded
As for drupal 5, in order to load the correct css file according to the language
we have set a small file load_rtl_core_css.php that check if there is RTL version of the css and load it insted of the regular file

all you need to do is replace

<?php print $styles; ?>  

in page.tpl.php with

<?php include_once 'load_rtl_core_css.php'; ?> 

here is the code

<?php
    $rtl_langs = array("ar", "fa", "he", "ur", "yi"); // There are a couple or so more. Put the codes of your RTL languages here
    if (in_array ($language, $rtl_langs)) { // Check if the language of the current page is RTL.
      /* Load RTL styles instead of default ones: */
      foreach($css as $media => $types){
        foreach($types as $type => $files){
          foreach($files as $file => $preprocess){
            $element = $file;
            $rtl_style = str_replace(".css","-rtl.css",$file);
            if(file_exists($rtl_style)){
              unset($css[$media][$type][$file]);
              $css[$media][$type][$rtl_style] = $preprocess;
            }
          }
        }
      }
      print drupal_get_css($css);
  	} else {
      print $styles;
  	}
  ?>

see here more themes that use this method
http://groups.drupal.org/node/13826