using a variable in the product description for a popup

[torvista]

In the product description text I want to use a link which will open a popup window using javascript.

The content of this window is a flash swf hosted offsite (it contains up-to-the-minute product information). There are two swf files that I want to be be retrieved, depending on the language selected at the time as I have a dual language shop.

As far as I understand I cannot link directly to the swf file, I need to embed it in some html to ensure it is handled properly by browsers without flash.

I have the popup working ok linking directly to a html file in my shop root.

<a href="javascript:popupWindow(\'define_ht_product_advisor_es.html\')">Product Advisor</a>

But I know it should not live there but in here

\includes\languages\english\html_includes\my_template folder

So, I make a new file

\includes\extra_datafiles\define_custom_filenames.php

with this in it

<?php
define(‘FILENAME_DEFINE_HT_PRODUCT_ADVISOR’, ‘define_ht_product_advisor’);
?>

and in

\includes\modules\pages\product_info\header_php.php

I put

$define_page = zen_get_file_directory(DIR_WS_LANGUAGES . $_SESSION['language'] . '/html_includes/', FILENAME_DEFINE_HT_PRODUCT_ADVISOR, 'false');

and if I test this using the $define_page variable in the template somewhere it gets loaded with the correct path ok.

The problem is how to use this in the javascript in the product description.

Using this in the description:

<a href="javascript:popupWindow(\'<?php echo $define_page ?>\')">Product Advisor</a>

gets stored and used literally so the html output to the browser is

<a href="javascript:popupWindow('<?php echo $define_page ?>')">Product Advisor</a>

So how should I be approaching this?

thanks
Steve