Start Date of Production Order in Past not allowed

Dear PP Gurus,

We are doing Production Order Migration where system date is 1st April , but Start date of it to be 31.03.2015. This is because WIP to uploadd needs to be reflected in MARCH period

Indicator "Start date allowed" in plant paramters is selected as "Allowed in Past"

Still Production order creation switches back to current date?

is there a way to achieve this.

Regards,

Jatin