how to disable compatibility check in excel while automating through c#

I am using Excel 2007 interop assembly to automate Excel through c#. Interop version is 12.0. When I try to save a file, it can be saved only in 2003 format, but thats fine with me, yet I am getting a popup saying compatibility issue. How can I disable this popup?

I have already tried workbook.CheckCompatibility = false and ExcelApp.DisplayAlerts = false so please tell if I am making other mistakes.

I have MS Office 2007 installed on my computer.

Thanks in advance.