Swathi,
You may want to consider the use of Sales Scheduling agreements.
Scheduling agreements contain a forecast component, but shipment and billing only take place when a delivery is created and PGI'd, typically when the order is released by the customer. Although these document types are commonly supported through EDI, it is entirely feasible to maintain them manually.
See SAP online help for an overview. For more detailed information, consult with your local SD expert, or enter your questions in one of the SD SCN forums.
Scheduling Agreements for Component Suppliers (SD-SLS-OA) - SAP Library
Best Regards,
DB49