here is some code I wrote (I own a CF-51)
first try this:
# modprobe panasonic_laptop

save the below as: /etc/acpi/events/hotkey

event=HKEY\ 00000080\ 000000(8[1-689]|0[37a])
action=/etc/acpi/hotkey.pl %e


save the below as: /etc/acpi/hotkeys.pl

then chmod +x /etc/acpi/hotkeys.pl

#!/usr/bin/perl

=begin comment

    Copyright (C) 2010 Mitchell Lafferty (<email address hidden>)

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see L<"http://www.gnu.org/licenses/">.

=end comment

=cut

use feature ":5.10";
use strict;
use warnings;

# 00000081 dn b
# 00000082 up b
# 00000084 mute
# 00000085 v dn
# 00000086 v up
# 00000007 ram sleep
# 00000089 batt
# 0000000a hdd sleep

#use YAML qw(DumpFile);
#$hash = {'BRIGHT_DN_STEPS' => 10,'BRIGHT_UP_STEPS' => 10};
#print DumpFile('/home/mitch/.acpi_config', $hash);

use constant {
    ACPI_BRIGHT_DN  => '00000081',
    ACPI_BRIGHT_UP  => '00000082',
    ACPI_SND_MUTE   => '00000084',
    ACPI_SND_DN     => '00000085',
    ACPI_SND_UP     => '00000086',
    ACPI_CRT_OUT    => '00000088',
    ACPI_BATT_KEY   => '00000089',
    ACPI_SLEEP_RAM  => '00000007',
    ACPI_SLEEP_HDD  => '0000000a',
    ACPI_PCC_BRIGHT => '/sys/devices/virtual/backlight/panasonic'
};

my $BRIGHT_UP_STEPS = 10;
my $BRIGHT_DN_STEPS = $BRIGHT_UP_STEPS;

my $SND_UP_STEPS = 1;
my $SND_DN_STEPS = $SND_UP_STEPS;

my ( $max_bright, $new_bright, $now_bright );

given ( $ARGV[3] ) {
    when (undef) {
        exit 0;
    }

    when (ACPI_BRIGHT_DN) {
        $max_bright = QuickOpen( ACPI_PCC_BRIGHT . '/max_brightness' );
        $now_bright = QuickOpen( ACPI_PCC_BRIGHT . '/brightness' );
        chomp($max_bright);
        chomp($now_bright);

        $new_bright = $now_bright - $BRIGHT_UP_STEPS;
        $new_bright = 0 if ( $new_bright < 0 );

        #~ print $max_bright," ", $now_bright," ", $new_bright, "\n";
        QuickWrite( ACPI_PCC_BRIGHT . '/brightness', "$new_bright\n" );
    }

    when (ACPI_BRIGHT_UP) {
        $max_bright = QuickOpen( ACPI_PCC_BRIGHT . '/max_brightness' );
        $now_bright = QuickOpen( ACPI_PCC_BRIGHT . '/brightness' );
        chomp($max_bright);
        chomp($now_bright);

        $new_bright = $now_bright + $BRIGHT_UP_STEPS;
        $new_bright = $max_bright if ( $new_bright > $max_bright );

        #~ print $max_bright," ", $now_bright," ", $new_bright, "\n";
        QuickWrite( ACPI_PCC_BRIGHT . '/brightness', "$new_bright\n" );
    }

    when (ACPI_SND_MUTE) {

        # don't care
        ...;
    }

    when (ACPI_SND_DN) {

        # don't care
        #~ system("amixer -q sset PCM,0 $SND_DN_STEPS-");
        ...;

    }

    when (ACPI_SND_UP) {

        # don't care
        #~ system("amixer -q sset PCM,0 $SND_UP_STEPS+");
        ...;
    }

    when (ACPI_CRT_OUT) {

        # don't care
        ...;
    }

    when (ACPI_BATT_KEY) {

        # don't care
        ...;
    }

    when (ACPI_SLEEP_RAM) {
        system('pm-suspend &');
    }

    when (ACPI_SLEEP_HDD) {
        system('pm-hibernate &');
    }

    default {
        die "What?: $ARGV[3]\n";
    }
}

sub QuickOpen {
    my $data;
    open( DAT, "<", shift ) || die "Err: read: $!\n";
    while (<DAT>) {
        $data .= $_;
    }
    close(DAT);
    return $data;
}

sub QuickWrite {
    open( DAT, ">", shift ) || die "Err: write: $!\n";
    print DAT shift;
    close(DAT);
}