archived BP should not be staffed in resource tab

Hi,

While doing resource staffing in resources tab, system is allowing to staff a BP even it is archived. I shud restrict an archived BP been staffed. I can do it programatically, but what i believe is SAP it self shud not allow a archived BP from staffing. Is there any standard way of doing this, any customization required?

Any idea on this?

Thanks,

Pavan.