void BillingEngine_EinvNodeAdded(object sender, MercatorUi.Engine.Gescom.BillingEngine.EinvNodeAddedEventArgs e)
{
    if ((e.Node.Name == "cbc:InvoicedQuantity") || (e.Node.Name == "cbc:CreditedQuantity"))
    {
        string s_unite = e.DrLigne["s_unite"].ToString();
        if (s_unite == "litre")
            e.Node.Attributes["unitCode"].Value = "LTR";
        else if (s_unite == "m")
            e.Node.Attributes["unitCode"].Value = "MTR";
        else if (s_unite == "m²")
            e.Node.Attributes["unitCode"].Value = "MTK";
        else if (s_unite == "m³")
            e.Node.Attributes["unitCode"].Value = "MTQ";
        else if (s_unite == "ångström") // ;-)
            e.Node.Attributes["unitCode"].Value = "A11";
    }
}