A file, named (by my own brain memory), سزعذ.xml when accessing the server with firefox, is listed as ????.xml in a DIR Operation.
Well, meaning they are special caracters.
<tns:dirResponse xmlns:tns="http://petals.ow2.org/components/ftp/version-3">
<tns:filename>test1.xml</tns:filename>
<tns:filename>test2.xml</tns:filename>
<tns:filename>test3.xml</tns:filename>
<tns:filename>titi.txt</tns:filename>
<tns:filename>toto.xml</tns:filename>
<tns:filename>????.xml</tns:filename>
</tns:dirResponse>