Print module can't load regions at views generated pages

I have added a 'header' variable in the pint_page preprocess function:

<?php
$vars['header'] = theme('header', array(
'front_page' => $vars['front_page'],
'logo' => $vars['logo'],
'site_title' => $vars['site_title'],
'site_name' => $vars['site_name'],
'site_slogan' => $vars['site_slogan'],
'search_box' => $vars['search_box'],
'header_line' => $vars['header_line'],
));
?>

Then I added

<?php print $header; ?>

to my print-page.tpl.php

Here is the code of header.tpl.php

<div id="header_box">
    <?php
      print $header_line; //region
    ?>
  </div>

And at the node print page it works perfectly. I see the content of $header_line region. But at the views generated page there is no $header_line content printed.

So the point is: how can I make print module print the content of heder.tpl.php file at the views generated page just like at the node print page?