add to cart problem

if I wanted to put the shopping cart button, even if the goods are not available, you can? is there any plug-ins? I have the business version of hikashop, but it gives me an opportunity to do so, I only have the chance to put the "whishlist"

Hi,

What do you really need ?
Allow customers to order products out of stock ?

If it is, we don't manage it actually but it's on our TODO list.