public static void Exec(MercatorUi.MovableControls.MovableButton clickedButton)
{
    // enter your customized code here
    MercatorUi.Forms.Billing.BillingForm billingForm = (MercatorUi.Forms.Billing.BillingForm)clickedButton.Form;
    billingForm.BillingEngine.CreateReceiptForThisOrder();
}