SMARTY: I would like To Know HOW I CUSTOMISING THE SEARCH BOX?

Hi at all, here I am again :)

Well, I have readed about the possibility to create the smartytemplate.php file where I can put my personal function.
Today I have readed this article http://drupal.org/node/45295 that explain how to custom the search box (I have found that on tha Aquasoft Theme (very nice!!!)).

By the way i will ask this, if I create this file:

smartytemplate.php

<?php
function smarty_search_theme_form($form) {
  return _smarty_callback('search-theme-form', array('form' => $form));
}
?>

And I wrote this file search-theme-form.tpl

<table border="0" cellpadding="0" cellspacing="0" width="100%">
  <tr>
    <td>
      <img src="<?php print base_path() . drupal_get_path('theme', 'SystemSight-Neutron') .'/images/spotlight_left.gif' ?>" alt="" />
    </td>
    <td width="100%" class="searchbox">
      <input maxlength="128" name="edit[search_theme_form_keys]" id="edit-search_theme_form_keys" size="15" value=" Search" onclick="value=''" title="Enter the terms you wish to search for." class="form-text" type="text">
      <input name="edit[form_id]" id="edit-form_id" value="search_theme_form" type="hidden">
    </td>
    <td>
	<input name="op" value="Search" class="form-submit" type="image" src="<?php print base_path() . drupal_get_path('theme', 'SystemSight-Neutron') .'/images/spotlight_clear.gif' ?>" alt="" />
    </td>
  </tr>
</table>

May I have the same result? Or I forget something?

Any Tip are very welcome!!!

Best Regards

Franco Tampieri