Deny users acess to a folder with PDF documents

Hi,

I recently created a folder containing a number of PDF-documents. I now want this folder(and its contents) to be inaccesible to everybody excepts users with the membership role "PDFROLE".

I thought whis addition to my web.config would do the trick (but it doesn't):










I imagine it has to do with the fact that PDF-s aren't handled by asp.net?

How can I achieve this? ...