public static void Exec(MercatorUi.MovableControls.MovableButton clickedButton)
{
    // enter your customized code here

    MercatorUi.Forms.Sig.SigForm sigForm = (MercatorUi.Forms.Sig.SigForm)clickedButton.Form;
    if (string.IsNullOrWhiteSpace(sigForm.DataSourceRow["c_id"].ToString()))
        return;
    DateTime[] dd = MercatorUi.Dialogs.AskDates("Facturen en creditnota's afdrukken tussen welke data ?");
    if (dd == null)
        return;
    string where_clause = string.Format("(pieds_v.id_cli='{0}') and (pieds_v.type=1) and (pieds_v.date between '{1}' and '{2}')",
        Api.UnquoteSql(sigForm.DataSourceRow["c_id"].ToString()),
        Api.DateTimeSelectString(dd[0]),
        Api.DateTimeSelectString(dd[1]));
    MercatorUi.Globals.Main.ShowHistAfterAutomaticProcedure("V", where_clause, true, null);
}