X-Cart forums - 2 Dropdown menus, 1 search

Anyone have any ideas on how to implement this please? I have tried generic forms found using google but can't get them to work in xcart... The code I have up to now inserts a dropdown box and submits a search when a particular option is selected. I would like it that 2 selections are made from seperate dropdown menus and the search is made based on the selections made (selection 1 + selection 2). Thanks.

Code:

{*

$Id: search.tpl,v 1.1 2010/05/21 08:32:02 joy Exp $

vim: set ts=2 sw=2 sts=2 et:

*}

<div class="search">

  <div class="valign-middle">

    <form method="post" action="search.php" name="productsearchform">



      <input type="hidden" name="simple_search" value="Y" />

      <input type="hidden" name="mode" value="search" />

      <input type="hidden" name="posted_data[by_title]" value="Y" />

      <input type="hidden" name="posted_data[by_descr]" value="Y" />

      <input type="hidden" name="posted_data[by_sku]" value="Y" />

      <input type="hidden" name="posted_data[search_in_subcategories]" value="Y" />

      <input type="hidden" name="posted_data[including]" value="all" />



      {strip}

 

   <select name="posted_data[substring]" onchange='this.form.submit()' class="{if not $search_prefilled.substring}black-text{/if}" value="{$search_prefilled.substring|default:$lng.lbl_search|escape}" />

<option>selection 1</option>

<option>selection 2</option>

<option>selection 3</option>



        {include file="customer/buttons/button2.tpl" type="input" style="image"}

      {/strip}



    </form>



  </div>

</div>

<br>