How to manage the post sale customer inventory

Summary

How to manage the post sale customer inventory

Content

I have a requirement to continue to manage the customer inventory after the sale, until the customer ask that the inventory be sent to him. ( the customer is basically wants to use our storages )

We perform the following transactions in the system  :
1) Customer Sales order shipping  
2) Customer Invoicing

but we keep the customer physical inventory in our subinventory until the customer is asking for it.

my question is how we can still manage the customer inventory in the system ( as non asset ) until the customer ask for it?