SD : credit management

Hi ,

I have done the required configuration for credit managemnet .

Now as per this config ,It shows every error I need .

But now my requirement is to put a check in Sales order change mode also .

Means when I am in change mode of sales order ( VA02) ,it is showing me the information message for overdue ,but its allowing to save the order .

I need this as per done in sales order creation mode .

Kindly help .