How to apply an IE6 specific stylesheet for a subtheme?

I have the following in my page.tpl.php

  <!--[if IE 6]>

    <?php if ($subtheme_directory && file_exists($subtheme_directory .'/ie6.css')): ?>
      <link rel="stylesheet" href="<?php print $base_path . $subtheme_directory; ?>/ie6.css" type="text/css">
    <?php else: ?>
      <link rel="stylesheet" href="<?php print $base_path . $directory; ?>/ie6.css" type="text/css">
    <?php endif; ?>

  <![endif]-->

The above code is mostly based on http://drupal.org/user/254346. I have also tried modifying the code to read as

 <!--[if IE 6]>
    <link rel="stylesheet" href="<?php print $base_path . $directory; ?>/ie6.css" type="text/css">
    <?php if ($subtheme_directory && file_exists($subtheme_directory .'/ie6.css')): ?>
      <link rel="stylesheet" href="<?php print $base_path . $subtheme_directory; ?>/ie6.css" type="text/css">
    <?php endif; ?>
  <![endif]-->

or

endif;

The above code is mostly based on http://drupal.org/user/254346. I have also tried modifying the code to read as

 <!--[if IE 6]>
      <link rel="stylesheet" href="<?php print $base_path . $subtheme_directory; ?>/ie6.css" type="text/css">
  <![endif]-->

There is a custom page.tpl.php file in the Zen subtheme and the ie6.css file exists in the correct sub theme folder yet none of the changes in the stylesheet is applied in ie6. The changes applied to the built in ie.css works fine but if I need to apply a change only to ie6, it just doesn't seem to be working.