sort menu items from xml

Hey guys i have an menu and populating it from a data base

here the code in c#:

 

protected void Page_Load(object sender, EventArgs e)
    {
        DataSet ds = new DataSet();
        using (SqlConnection conn = new SqlConnection(connStr))
        {
            string sql = "Select id, title, parent_id, url from menu";
            SqlDataAdapter da = new SqlDataAdapter(sql, conn);
            da.Fill(ds);
            da.Dispose();
        }

        ds.DataSetName = "Menus";
        ds.Tables[0].TableName = "menu";
        DataRelation relation = new DataRelation("ParentChild", ds.Tables["menu"].Columns["id"], ds.Tables["menu"].Columns["parent_id"], true);

        relation.Nested = true;
        ds.Relations.Add(relation);

        xmlDataSource.Data = ds.GetXml();
    }

Select allOpen in new window

my problem is, how do to do a sort on the sub menus?