Hi,
With links, we could give you more information.
The add to cart button is not display directly in the "show_default" view, it uses another template named "quantity".
<div id="hikashop_product_quantity_main" class="hikashop_product_quantity_main">
<?php
$this->row = & $this->element;
$this->ajax = 'if(hikashopCheckChangeForm(\'item\',\'hikashop_product_form\')){ return hikashopModifyQuantity(\'' . $this->row->product_id . '\',field,1' . $form . ',\'cart\'); } else { return false; }';
$this->setLayout('quantity');
echo $this->loadTemplate();
?>
</div>
This is this block that you have to move if you want to move the "add to cart" button in the page.
Regards,