Custom Duty Refunds - Any Experience Out There?

Starting last year, i've been buying gift products for export to USA. I purchase the product then have it improved and decorated with the help of 2 thai employees in my rented shophouse. Acording to a link I found on this page:

"Duty refund Goods such as raw materials used in producing, processing or packaging items for export, may be imported under a system allowing for duties paid to be refunded or for a guarantee to be posted. The items so imported must be re-exported within the time stipulated under Customs regulations. Goods imported which are not processed in any way and not kept in a bonded warehouse are eligible for a partial duty refund equal to 90% of the duty paid or the entire duty paid in excess of Baht 1,000, whichever is higher"

I want to bring in some product from China to process in my Thai shophouse but i'm not sure if finished products will qualify for a refund. Anyone have any experience or better yet a contact with a reliable (and small) customs broker?