date issue in Planned orders

Hi PP experts,

I have one requirement from the client. We are running Lead time scheduling and capacity planning, based on the MRP run we get some planned order.

I have an planned order whose Basic start date is:15/09/2009 and Basic finish date:18/09/2009. Also the planned order has got production start date as:18/09/2009 and production end date as 18/09/2009.

Now If i look at the planned order in display mode, the requirement date is 18/09/2009. i.e always on production start date.but the client wants this date as Basic start date (15/09/2009).

Could any one suggest me how to get this date in planned order.

Thanks and Regards

Purushotham