In order to show add to cart button in up sell products i have added an upsell.phtml file inside app/design/frontend/your_package/your_theme/template/catalog/product/list/
my code for upsell.phtml file is
<form action="<?php echo $this->getAddToCartUrl($_link) ?>" method="post"
id="product_addtocart_form_<?php echo $_link->getId()?>"<?php if($_link-
>getOptions()): ?> enctype="multipart/form-data"<?php endif; ?>>
<?php if(!$_link->isGrouped()): ?>
<input type="text" name="qty" id="qty" maxlength="12" value="<?php echo
($this->getMinimalQty($_link)?$this->getMinimalQty($_link):1) ?>" />
<label for="qty"><?php echo $this->__('Qty') ?>:</label>
<?php endif; ?>
<button type="button" onclick="this.form.submit()"><span><span><span><?php echo $this->__('Add to Cart') ?></span></span></span></button>
Unfortunately add to cart button is not showing up in upsell.phtml file. Please help me achieve this, thanks