Most often the recommendation is to export as a Merge file "export.mer" It puts the Field name in the first line.
Some say name the file "export.csv" even if it is a .mer filetype.
Others say make a record with the desired names in the record, you also would probably need a field for sorting to get that record to the first position.
I just published a blog post on custom column names when exporting from FileMaker to Excel: http://www.clickworks.be/en/filemaker-export-excel-custom-column-names
Maybe it could be a solution to your problem.