WBS assignement in Sales Order

Hi Gurus,

My client is a Software Compnay. While i creating a sales order i have to assigne a WBS element into the sales order( Account Assignment tab-item level).

But here system should accept the WBS element against the projects which are released only.

But eventhough the project are not release the system is accepting the WBS element into Sales order iwant to restrict this.

Can anybosy help me in this.

Cheers,

Sumith