[imp] MIME attachment filename encoding other than utf-8

[JinSoo Suh]

I use Horde 3.1-cvs and IMP 4.1-cvs.
 
I composed new message with chaset "Korean (EUC-KR)"
and attached a file with korean name.
 
The received mail header encoded with "euc-kr"
but MIME attachment filename encoded with "utf-8".
 
Firefox can download this attachment with correct Korean name.
But MSIE download this attachment with weird name.
 
How to make IMP to encode MIME attachment filename with "euc-kr"?
(This problem also occurred in Horde-3.0.4 / IMP H3 (4.0.3).)
 
Here is a part of the message:
 
Subject: =?euc-kr?b?xde9usau?=
MIME-Version: 1.0
Content-Type: multipart/mixed;
        boundary="=_2z83e3neceuc"
Content-Transfer-Encoding: 7bit
User-Agent: Internet Messaging Program (IMP) 4.1-cvs
This message is in MIME format.
--=_2z83e3neceuc
Content-Type: text/plain;
        charset=EUC-KR;
        format="flowed"
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable
=C5=D7=BD=BA=C6=AE
--=_2z83e3neceuc
Content-Type: image/pjpeg;
        name="=?utf-8?b?7YU=?= =?utf-8?b?jOyKpO2KuC5qcGc=?="
Content-Disposition: attachment;
        filename="=?utf-8?b?7YU=?= =?utf-8?b?jOyKpO2KuC5qcGc=?="
Content-Transfer-Encoding: base64