how to change the charset of responsing message from us-ascii into euc-kr?

I'm using Fedora core6
and installed mj2(majordomo-current.tar.gz)

I want to change the responging mesages(for example... welcome message) into
korean character..
but....when I converted the file welcome into korean charcter
I got corrupted response messge...
because the defulat charset is us-ascii...

how to change the charset of responsing message from us-ascii into euc-kr?

I tried to chage file enconding type.....while vim   I commanedd   :w
fileencoding=euc-kr... or utf-8

but....whenever I try to test ....always I got us-ascii file....so I can't
read korean character welcome message
I must change encoding type into utf-8 or euc-kr in Browser to see the
contents...

tell me the way to change this default charset from us-ascii to another
charset.......pls

regards..