buy 10 button

[spidermax]

trying to make a button that a customer can click when there is a bulk discount ie buy 10 get 15% off this is the code i have added but it does not seem to work on the page it self (it shows) any one able to help?

<input type="hidden" name="token" value="{$static_token}" />
		    <input type="hidden" name="id_product" value="{$product->id|intval}" id="product_page_product_id" />
		    <input type="hidden" name="add" value="1" />
		    <input type="hidden" name="id_product_attribute" id="idCombination" value="" />
		    <tr>

		    <th>
		    {convertPrice price=($productPrice)-(($productPrice / 100) * ($quantity_discount.real_value|floatval))}

		    {l s='each if you buy '}
		    <input type="text" name="qty" id="quantity_wanted" class="text" value="{$quantity_discount.quantity|intval}" size="2" maxlength="3" {if $product->minimal_quantity > 1}onkeyup="checkMinimalQuantity({$product->minimal_quantity});"{/if} />
		    <input type="submit" name="Submit" value="{l s='Add to cart'}" class="exclusive" />