CFSpreadsheet borders for Merged Cells

I searched around for this for awhile, so forgive me if there is an answer already. I am having trouble applying borders to merged cells using CFSpreadsheet. Below is some example code.

<cfscript>
newSS = SpreadsheetNew('Testing');      //Create Spreadsheet    

SpreadsheetMergeCells(newSS,1,1,1,9);
SpreadsheetAddRow(newSS,'Underline this Header');
SpreadSheetFormatCell(newSS,{bold=true,alignment='center',bottomborder='thin'},1,1);    

Spreadsheetwrite(newSS,expandpath('myTest.xls'),true);  //Write File
</cfscript>

What I would expect is the top cell to be underlined all the way across. What I get is the top cell only underlined through column "A" and not underlined after. Is there anyway around this or is this just a limitation of CFSpreadsheet??

Thanks!