Exit for VA01

Dear All,

While creating sales order, When I enter material no,plant and date and hit enter it shows a warning message (BOM not present for this specific material) and the sales order gets created.

But the requirement is When the BOM and routing is absent for the specific material,it should show an error message and the sales order should not be saved.

I found some exits for it. The include is MV45AFZB.

Can you tell me,what exit can I use? And if this is not the correct way, Can you tell me how can I do that?

Thanks