Quotes added to filename when downloading file from salesforce with mozilla firefox

I have just upgraded FTP Attachment to version 4.8 on an IIS server, on which is connected our saleforce org.

From that moment I still can add an attachment to a request, but when I get it back with mozilla firefox, it is downloaded with a filename surrounded by quotes. Moreover if the name contains a space, the name is simply truncated!

This doesn't happen when using Chrome or Opera.

This happens to my collegues too, it is not specific to my computer.

This didn't happen in version 4.6.

Have someone this problem? The support doesn't answer me yet.

Regards