my $msg = MIME::Lite::TT::HTML->new(

    From        => $mail_header->{From},
    To          => $mail_header->{To},
    Cc          => $mail_header->{Cc},
    Subject     => $mail_header->{Subject},

    Template   => {
        html => $self->{html_tt2},
        text => $self->{txt_tt2},
    },
    TmplOptions => {
        INCLUDE_PATH => INCLUDE_PATH_EMAIL_TT2,
    },
    TmplParams => $vars,

);

$msg->attr("content-type"  => "multipart/mixed");

for each attachment:
    $msg->attach(

        Type        => $attachment->{Type},
        Path        => $filepath,
        Filename    => $attachment->{Filename},
        Disposition => 'attachment',

    );
end

$msg->send;