@Ivanko
Osclass team use Update URI to find proper product to be updated. This is not too efficient as it is generated based on product name and may be changed when product is changed.
We, based on prestashop example, has started to use product key. Key is generated automatically by osclass point as is not related to product name, provides unique identificator and is easy to update and maintain for anyone that want to sell on osclasspoint.com.