Not able to write in published workbook using Excel Service SetRan

[Matt]

Hello,
I have a Windows application used to read a workbook (sheet1,
EmployeeListRange) through Excel Web Service and display the returned values
in a DataGridView. This part is working fine using Excel Web Service'
GetRangeA1() web method.

Next, I would like to add more enties in DataGridView and save all items in
the previous workbook using Excel Web Service' SetRangeA1() method but this
operation just does work. There is no SOAPException generated. Here is a
portion of the code used to submit the dataGridView data (employeeList array)

try
{
status = excelServ.SetRangeA1(sessionId, "Sheet1", "EmployeeListRange",
employeeList);
}
catch (SoapException ex)
{
Console.WriteLine("SOAP Exception Message: {0}", ex.Message);
}

Is there any additional setup I have to perform on my MOSS server?
Please help!
Matt