Yes. Sending the encrypted file as "test.fdf" just confuses Acrobat.

On the Outlook end, I developed a VBA macro to automatically save the attachment as an FDF file. This seems to work OK.

I'm using Network Associates' PGP Desktop Security 7.0. When I open the test e-mail in Outlook, when I select the Save Attachment command or run the macro, I'm prompted for the pass phrase for the key I'm using.

The only flaw with the PDF::FDF::Simple module is that it doesn't seem to have a method for adding the /F key, which associates the FDF file with a PDF form.