I wil wade in on this, as there is a LOT of confusion on it.
Google have a couple of systems, and there are a LOT of plugins for carts such as OSCommerce, ZenCart, cube cart etc. but the problem here is that these are google BASE feeds.
This is where the confusion arises, Google base is NOT google products. The product links that appear at the head of the SERP's are not google base feeds, they are google products items (I am using items rather than products to try and avoid confusion).
MOST google BASE feeds include the 'location' attribute, but using this attribute means that you are automatically excluded from Google prooducts, as you are seen as selling a LOCAL item, so you go to google local (base).
If anyone is having a problem here with this, please state
1. shpopping cart
2. plugin used
3. manual fields
that way I can throw in some more help
Took me an age of uploading file after file to get a set of products showing
