Unless I'm misunderstanding what you want, Adagio doesn't have one. You can kluge together a workable system if you are willing to compromise, using Purchase Orders for Adagio, Adagio Invoices, Adagio Inventory and Adagio JobCost. I don't think you will be able to use OrderEntry to do your billing.

Is there a specific reason why you want to use Adagio?

Steve