ogletree - 3:23 am on Feb 2, 2010 (gmt 0)
That is not really a link. That is a form submission. I have not tested it but I'm pretty sure Google dose not count that as a link.
When you say "Every product on my site goes to a third party cart" do you mean that the product page is on your site but the buy now button goes to another site? If so I think you have it set up correctly.