zen cart: v1.3.9h

I have added this hack, you can see it here http://www.melianpetsupplies.co.uk/i...roducts_id=329

it is showing stock number available for each product that has been set in 'stock by attributes', but customers are still allowed to order the products that dont have stock amount added

Allow Checkout is set to false, so, products in stock by attributes that have no stock, or not added to list should be disabled and users should not be able to check out, but they can still...

anyone know of any hack that will sort this?

I have had many probs trying to config stock by attribtes, for years, would be good to finally get it nailed