Availability check in Consigment stock

Hi Gurus,

Here is my requirement.

When i do the avaialbility check i should first check whether the material is available in Customer consignment stock already or not. Need to check the stock which is delivered as part of Consignment Issue.

Here i just i have to verify that for a particular customer and for a material any open Consignment Issued stock is there or not because this is managed in BAPI.

What are the tables i need to look into to achieve this?

Thank you

ANil