I'm wondering why you're calling it a 'conceptual basket', which may be harder terminology for users to understand?
Why not just have orders with different statuses?
I.e. Open order, closed order, placed order, etc etc? This is much easier to understand concept and terminology and may help the users feel in control?
Personally with baskets I worry that should I navigate away from the site, will the basket empty, will it save the basket. However if I have opened an order, added to an order, but not yet placed the order and paid for it I can go back and amend the order?
Just a suggestion.
Hope this helps