Pulling future requirement ahead due to supply constraint

Hi,

I have following scenario:

Raw material Supply and finished product demand follows inverse curve, i.e., say for example raw material supply is more during Mar-July time frame whereas demand for finished product is more during say Sept - Jan time frame.

Raw material have short shelf life..so generally we produce for Sept-Jan requirement during Mar-July time frame and store the product to meet demand during Sepr-Jan time frame.

Question:

In APO, when I am doing long term planning, using SNP, let me know how I can pull planned orders (to meet demand during Sept-Jan) close to raw material supply, say sometime during Mar-July.

Let me know if anybody has come across this scenario and has any inputs.

Thanks

Sharad