We don't use the Office Connector.  But, when you print the file, you could print it to a text file, open the text file with Excel and set your columns that will be delimited with commas, remove the column headings and the page headings, and then save as a CSV file from Excel. 

Another option would be through Report Designer.  Open the Invoices Selected for Payment report, immediately save as "Invoices Selected for Payment for Upload" and then play around with the new file.  What I've found is that column headings and page headings not not play well with Excel, so I'd remove those completely from the design.  Save the new design and then print it to an .xls file.  Then open .xls file and save it again as a CVS file.