LineItemId is -1

Hi,

We are using serialized carts to store cart content. When saving the line item, I notice that the id for all line items are -1 in the SerializableCart-table in the database, whereas the line items have IDs in Commerce Manager. Is it supposed to be like that? Could we, when loading the cart and its line items, get hold of the line item id as seen in Commerce Manager? 

Here is an outline of what I'm doing when creating the cart.

var cart = _orderRepository.LoadOrCreateCart<ICart>(contactId, nameOfCart);

var lineItem = cart.CreateLineItem(code, _orderGroupFactory);

cart.AddLineItem(lineItem, _orderGroupFactory);

_orderRepository.Save(cart);

And later, when loading the created cart, the line item ids are all -1. Why is that?

var loadedCart =_orderRepository.LoadCart<ICart>(contactId, nameOfCart);

Thanks!

/Jessica