Changing case of UTF-8 strings

Hi all,

I'm trying to change case of UTF-8 strings. I've read a bunch of
do***entation, but can't figure out how to do it right. Here is an
example:

=3D=3D=3D My code:
use strict;
use utf8;

my $line;
my $letter;

while ($line =3D <STDIN>) {
    chomp($line);
    utf8::upgrade($line);
    $line =3D lc($line);
    print "${line}\n";
}
=3D=3D=3D Data file:
ANDR=C3=89 DA SILVA
=C3=82NGELO DE SOUZA
=3D=3D=3D Execution (perl 5.8.8):
$ ./lower.pl < names > output
=3D=3D=3D Output
andr=EF=BF=BD=EF=BF=BD da silva
=EF=BF=BD=EF=BF=BDngelo de souza
=3D=3D=3D

As you may notice, I managed to change the special character into
something. But not the corresponding lower case UTF-8 letter. Please
help.