We have created Sales Orders for each of our customer who has assigned us the Work Orders (POs).

In our case, 1 Sales Order has many items that get billed to the customer over a year or more.

What we want to be able to do, is 

Plan and earmark the amounts that will be billed in future, to see the potential invoices that will be raised in each month for different parts of the same sales order.

We want to see our Future Invoices right now, to see the monthly Invoicing targets. These invoices should not get calculated for GST or as Annual Income.

Any ideas on how to achieve this?