I am really struggling to get my head around how to treat Consignment stock in the Items module.

I bring the stock in at zero value to rework it into a finished product.
Whatever I use, I have to buy from the supplier with a supplier invoice at the value agreed, this will double up my stock quantities
when I sell the stock I need to decide whether I sell it from the zero value stock or the newly purchased stock - but that will not update my original consignment stock

yes, I am confusing myself here !

please help if any of you have a foolproof process for this

Elsa