Set minimum cart quantity in wp e-commerce

Hi All

I really hope someone can help me. I’m trying to add a minimum cart quantity to wp e-commerce. I’ve gotten as far as editing the wpsc-cart_widget.php file and changed the cart item count from > 0 to >= 3

The problem I’m having now is it wont even show me the items in my cart until I have at least 3 items in it.

Now what I actually want is the checkout to only become available once there are 3 items listed.