希望使用Excel二进制格式在Excel中添加工作表

下面的代码片段取自http://network.convergenceservices.in/forum/5-components/2191-export-excel-a-new-way.html

function xlsBOF() {
            echo pack("ssssss", 0x809, 0x8, 0x0, 0x10, 0x0, 0x0);
            return;
        }
        function xlsEOF() {
            echo pack("ss", 0x0A, 0x00);
            return;
        }
        function xlsWriteNumber($Row, $Col, $Value) {
            echo pack("sssss", 0x203, 14, $Row, $Col, 0x0);
            echo pack("d", $Value);
            return;
        }
        function xlsWriteLabel($Row, $Col, $Value ) {
            $L = strlen($Value);
            echo pack("ssssss", 0x204, 8 + $L, $Row, $Col, 0x0, $L);
            echo $Value;
            return;
        }

    header("Pragma: public");
    header("Expires: 0");
    header("Cache-Control: must-revalidate, post-check=0, pre-check=0");
    header("Content-Type: application/force-download");
    header("Content-Type: application/octet-stream");
    header("Content-Type: application/download");;
    header("Content-Disposition: attachment;filename=vandetailslist.xls ");
    header("Content-Transfer-Encoding: binary");
    xlsBOF();
    xlsWriteLabel(0,0,"Column 1");
    xlsWriteLabel(0,1,"Column 2");
    xlsWriteLabel(0,2,"Column 3");
    xlsWriteLabel(0,3,"Column 4");
    $xlsRow = 1;
    foreach($somearray as $value)
    {
        xlsWriteNumber($xlsRow,0,"{Column Value 1}");
        xlsWriteLabel($xlsRow,1,"{Column Value 2}");
        xlsWriteLabel($xlsRow,2,"{Column Value 3}");
        xlsWriteLabel($xlsRow,3,"{Column Value 4}");
        $xlsRow++;
    }
    xlsEOF();
    exit; 

问题是，我想每个工作表只添加10条记录，如果数据更多，我想添加一个新的工作表，并开始在那里添加行。我找不到添加新工作表的方法。任何帮助都将不胜感激。