I finally manage to have my KDE power control, screen brightness, working, as well as, I am now able to suspend to RAM or Hibernate to disk also working from KDE.

First I must say that I had all of that working from the command line, I also have installed and working cpufreq

So, the only needed step to have this working was to configure, /etc/Policykit/Policykit.conf

Edit it with your favorite text editor as root

It should look like this:

< ?xml version="1.0" encoding="UTF-8"?> <!-- -*- XML -*- -->

< !DOCTYPE pkconfig PUBLIC "-//freedesktop//DTD PolicyKit Configuration 1.0//EN"
"http://hal.freedesktop.org/releases/PolicyKit/1.0/config.dtd">                

< !-- See the manual page PolicyKit.conf(5) for file format -->

< config version="0.1">
< match user="ggarron">
               < match action="org.freedesktop.hal.storage.*">
                       < return result="yes"/>                
               < /match>                                      
               < match action="hal-storage-mount-fixed-extra-options">
                                              
               < /match>                                              
               < match action="hal-storage-mount-removable-extra-options">
                       < return result="yes" />                           
               < /match>                                                  
< /match>                                                                          
                                                                                                                             
    < match user="ggarron">                                                
        < match action="org.freedesktop.hal.power-management.shutdown">
            < return result="yes"/>
        < /match>
        < match action="org.freedesktop.hal.power-management.reboot">
            < return result="yes"/>
        < /match>
    < /match>

< match action="org.freedesktop.hal.power-management.lcd-panel">
      < match user="ggarron">
          < return result="yes"/>
      < /match>
< /match>

< match action="org.freedesktop.hal.power-management.cpufreq">
      < match user="ggarron">
          < return result="yes"/>
        < /match>
< /match>

< match action="org.freedesktop.hal.power-management.suspend">
    < match user="ggarron">
        < return result="yes"/>
    < /match>
< /match>


< match action="org.freedesktop.hal.power-management.hibernate">
    < match user="ggarron">
        < return result="yes"/>
    < /match>
< /match>


< /config>

That text is modified so you can see it on this page, there is a space added after each "<" symbol, that you need to delete for it to work.

After this, restart hal daemon, and also KDE, you may better restart your laptop instead.

Here is the text file of the above /etc/Policykit/Policykit.conf file, so you can just copy and paste, be sure to change "ggarron" by your own username.

Sources:

http://wiki.archlinux.org/index.php/HAL#Permission_Denied
http://bbs.archlinux.org/viewtopic.php?id=65070
http://bbs.archlinux.org/viewtopic.php?id=65038