I was reading over your the SiteCatalyst Tag and E-Commerce Extension articles and typically seeing product_id mapped to a sku. With the general format for s.products= product_category;product_id;product_quantity;product_price I do not see another identifier to distingush between products with the same SKU. We have this issue on our cart page, but we also include a unique 'ItemId' for each product. In the E-Commerce Extension article I see _cprod and _csku but both are mapped to product_sku. Is this standard practice? It seems in our case _cprod would be ideal for our 'ItemId'. Could you explain how having a different _cprod and _csku values impacts the s.products string? On the cart page, we are going to want to track, qty changes, removals, product edits etc for each product so we need both the sku and itemid reported when these events are fired. Thanks