Mail plugin attachment with special char

I’ve got a problem reading the attachment name when that name contains special chars. When I have the following attachment: Italië.jpg, it gives the following attachment name: “=?iso-8859-1?Q?Itali=EB=2Ejpg?=”

When I change the filename of the attachment into: Italie.jpg it works correctly so the problem is just in the ë. Is there any way that I can read those filenames correctly?