[Plugin: WooCommerce – eCommerce plugin for WordPress] External Product links

In my shopping cart, I have a few of my own products, and I also sell affiliate products.

For these affiliate products, instead of add-to-cart button, I want to have buy now button, which redirects the user to the external product link.

This feature is available in wp-ecommerce, marketpress, e-shop, etc.

how can i do this in woocommerce? if the feature is not directly available, what is the work around?

http://wordpress.org/extend/plugins/woocommerce/