OK, so i found the solution.
The kind of mime format that i get when draggin an outlook attachment is "application/x-qt-windows-mime;value="FileGroupDescriptorW""
I have no url or filename, but i can get the content of the attachment via event->mimeData->data("FileContents");
Then i write that into a QFile and i am ready to go and do something with that file.

Bye.