Creation of Billing with reference to the Sales Order

Dear Friends,

I need your suggestion for the following scenario.

Client wants to create the Billing Document with reference to the Sales order.I mean when he is entering sales Order while creating the billing document ,the system should generate the billing document only for the delivered quantity.

e.g sales order is created for 100 Tons.And there are 5 delivery documents for 50 Tons.(Still the Sales order is open).

Now when billing document is created with reference to the sales order ( Not with reference to the Delivery Document) it should create the billing document only for these five deliveries.

Is it possible? If yes,how?

Thanks in advance.

Regards,

Shrikant