How to Override File Version Renaming (e.g., _0, _1)

I need to force a double file extension (e.g., .pdf.pdf) to overcome an Outlook (grrr, argh) issue that breaks email attachment links.

FileField Paths works fine with tokens on the first upload (e.g., examplename_exampletoken.pdf.pdf) but successive uploads of a particular file end up with the version inserted in a way that makes sense but foils my hack (e.g, examplename_exampletoken.pdf_0.pdf).

I thought the Active Updating option in FileField Paths would do the trick by keeping the desired name on the latest file, but when enabled it generates errors on my install ("The selected file /var/www/vhosts/example.com/httpsdocs could not be copied".).

I've looked around in FileField Paths and FileField but I can't figure out how to get around this - any suggestions would be much appreciated.