VAT invoice out of Project Contract


Please can I be clarified on generating customer invoice out of Project Contract.

My understanding is Project Contract holds combination of Purchase Orders and contract is executed. But what if customer ends up asking for VAT invoice?

How do we handle this scenario in AX 2012? How do we best generate SO invoice for the customer without PO number being displayed and showing consolidated description of sale rather full info from project in the invoice.

Hope i have managed to clarify my query.

Awaiting response.