void BillingEngine_EinvNodeAdded(object sender, MercatorUi.Engine.Gescom.BillingEngine.EinvNodeAddedEventArgs e)
{
    MercatorUi.Engine.Gescom.BillingEngine billingEngine = (MercatorUi.Engine.Gescom.BillingEngine)sender;
    if ((e.Node.Name == "cbc:LineExtensionAmount") && ((e.ParentNode.Name == "cac:InvoiceLine") || (e.ParentNode.Name == "cac:CreditNoteLine")) && (e.DrLigne["commande"].ToString() != string.Empty))
    {
        XmlNode n = billingEngine.EinvAddNode(e.eInvoiceEnum, e.ParentNode, "cac:OrderLineReference");
        billingEngine.EinvAddNode(e.eInvoiceEnum, n, "cbc:LineID", e.DrLigne["commande"].ToString());
    }
}