Hi there,
I'm glad to hear that you have solved it.
First, it's important to note that the cart goal doesn't deal with actual logic in the cart. It just shows some offers based on your specifications.
So, regarding the Free Shipping option, there are 2 ways to handle it.
The first one is to offer it as a discount through the Shopify Discounts settings.
http://www.shopify.com/admin/discounts

The second one is to create a new shipping rate for your shipping profile based on the order total, as seen in the screenshot below.

Let me know if you still need further assistance with this matter.