can any some buddy tell me how too add a varible to the cart action?

i made some varible input on the product info page that works well. but when i put into my "add cart" then my select is gone.

here is the code i use:
<?php
$maat_array[] = array(array('id' => '', 'text' => ""));
$maat = $db->Execute("select maat_id, euro_maat
from product_maat
where groep ='" .($product_size_id). "' order by euro_maat");

while (!$maat->EOF) {
$maat_array[] = array('id' => $maat->fields['maat_id'],
'text' => $maat->fields['euro_maat']);
$maat->MoveNext();
}


?>

<?php echo Maat ?>
<?php echo zen_draw_separator('pixel_trans.gif', '24', '15') . '&nbsp;' . zen_draw_pull_down_menu('select_maat', $maat_array ,$select_maat-> maat); ?>
<br /><br />



sorry for my bad english

http://www.bedrijfskledingurzo.nl/we...products_id=10