Creating port as a plant (Depot)

Dear All,

I need you opening on this scenario.

My client import liquid chemical for manufacturing purpose, they import chemical in bulk eg 100000L of chemical.

But they don’t have that much capacity of storage in there plant. Hence they take storage tank on rent from Port department.

So whenever they required certain quantity of chemical they transfer it from port to manufacturing plant.

Now my client requirement is that :-

1. They want to create PO in their manufacturing Plant, i.e liability should be booked in manufacturing plant.
2. Capture excise only on quantity they transfer from port to plant and not on full quantity they import.
3. They want to show total stock (100000 L) in their balance sheet of manufacturing plant.

How can we full fill above requirement.

I checked below link but don't find helpful.

Thanks in advance.

Shayam