Permalinks fix

Hi all,

I changed my permalinks’ stucture and I get both right and “not so right” results. Let me explain:

My website includes an e-shop and some articles. I want the link stucture to be: http://www.site.com/shop/prod_category/product. When I click on a category, the link becomes http://www.site.com/product_category/category_name i.e. http://www.site.com/product_category/category_a

“products_category” stays and then follows the actual category name.

When I click on a product, everything works fine.

Any ideas, on what to change?

Thanks