<?php if ($_helper = Mage::registry('templateHelper')): ?>
<?php
    $_data = array(
        'is_overview' => isset($_isOverview) && $_isOverview,
        'context' => $this,
        'product' => $_product
    );
    echo $_helper->createTemplate('product/buy', @id)->addData($_data)->toHtml()
?>
<?php endif ?>