SS,
You don't. Demand related to the planning material never reaches the linked Finished goods materials, it is not supposed to.
In general, in Strategy 60, the only demand for a planning material is forecast (planned independent requirements).
In general, in Strategy 60, the only demand for a Finished Goods is actual sales demand (sales orders).
The unique characteristic of Planning-Material-based strategies is that the Forecast for the planning material is consumed by sales for the linked products. This allows sales orders for many FGs to consume a single forecast. Much easier than trying to forecast each FGs individually, or trying to forecast the FGs using historical ratios.
Typically, the planning material has a BOM, and the BOM components are materials that all of the BOMs of the linked FGs have in common. So, by entering the PIR for the Planning Material, production for the SemiFinished Goods can be started. Then, when the sales orders are entered, the SFGs are already being produced.
For more info, look in help.sap.com. Search on "Planning with a Planning Material". There is a nice description, with some examples.
Best Regards,
DB49