Using Jigoshop, how can I add a custom post type to the cart via code?

Question

I want to programmatically add an item to the cart, and that item is not a product.. It's a custom post type that I am creating. I think I'm going in the right direction by using the Jigoshop cart class. Found in the jigoshop folder under classes/jigoshop_cart.class.php. The problem is that I'm not sure exactly how to hook something into it that is not a product.. I thought maybe someone could point me the right direction.

Thanks in advance!