EMAIL: Extended Characters in SUBJECT field

[Sean O'Dwyer]

Using this code, as I've used for ages in many scripts, causes an error
on a Spanish language site I'm devloping.

print MAIL "MIME-Version: 1.0\n";
print MAIL "Content-type: text/plain; charset=iso-8859-1\n";
print MAIL "Content-transfer-encoding: quoted-printable\n";
print MAIL "Subject: Confirmacion\n\n";

"Confirmacion" should have an accent over the second "o" but my
newsreader won't let me type the character directly.

The error is that sendmail sends the e-mail correctly, but the recipient
sees the subject messily formatted as...

Subject: =?UNKNOWN?Q?Confirmaci=F3n?=

How can I encode this character properly in the script, so the accent
appears over the "o"?

(The Perl source file is uploaded as ISO Western Latin 1.)

Thanks in advance,

Sean