private void DisplayMap_Load(object sender, EventArgs e)
        {
             .........
            (sql2008Layer.FeatureSource as MsSql2008FeatureSource).ExecutingSqlStatement += new EventHandler<ExecutingSqlStatementMsSql2008FeatureSourceEventArgs>(DisplayShapeMap_ExecutingSqlStatement);
sql2008Layer.CustomGeometryColumnName = YourGeometryColumnNameCorrespondingToSpatialIndexName;
            ...........
        }
        private int counter = 0;
        private string indexname = yourspatialindexname;
        void DisplayShapeMap_ExecutingSqlStatement(object sender, ExecutingSqlStatementMsSql2008FeatureSourceEventArgs e)
        {
            if (e.ExecutingSqlStatementType == ExecutingSqlStatementType.BuildIndex)
            {
                if (counter == 1)
                {
                    string addedSql = "And sys.indexes.name='" + indexname + "';";
                    e.SqlStatement = e.SqlStatement.Replace(";", addedSql);

                }
                counter++;
            }
        }