Converting xls to txt by Excel.Workbook.SaveAs in c# .net 4

Have a problem. I convert xls table by "Excel.Workbook.SaveAs" and in final txt file all numbers that are bigger than 999 are showed like: "2,300" with coma and quotes. I convert xls table in excel application by clicking "save as" and choosing txt format (with tab separators) and in final txt file all numbers that are bigger than 999 are showed like: 2 300 without quotes and coma. I need to convert that with "save as" method and recieve normal txt file without quotes and comas. I tried to use all text formats in the "save as" method and that haven't gave me necessary result. Thank you in advance!