THird Party PO Scenario - GR into Customer Consignment Stock

HI,

In a Third party scenario, is there any possible way to post the GR into Customer consignment stock ?!

In std SAP,

PR is generated from Sales order and the PO is created w.r.to the PR.

PR & PO will have the acct assignment ( sales order) and item category (third party).

during GR, we can't see the stock in the system. because the GR is statistical one since the stock is directly deliverd at customer place.

But in the current world in our case,

the stock is delivered in an external warehouse, from where the goods will be delivered to customer at a later point.

we want to track the stock in external warehouse. so, we want to have this as the "customer consignment stock". ( we may have this as a SLOC and from there we can transfer to customer consignment stock. but there will not be any link for the sales order and this customer consignment stock and moreover during GR we are not updating the stock...)

SO here is the question,

how can we update the stock during GR for Third party order( as far as I know, we can't define new item category).

?!

If we are updating the stock during GR for 3rd party, then we may find a way to post it to the customer consignment....

Pls share your ideas..thanks.