This is a step in my private EEEPC set up protocol, which I wrote down to be able to recover after a total reset.  It works for me, I hope it will for you, but I give no guarantees.
(BTW: Most of the other parts of my recovery protocol come from this wiki, THANK YOU to all the authors out there, this is my small way of paying it forward.)

(Note: My step 7) is to activate Xandros repositories, as in     http://wiki.eeeuser.com/addingxandrosrepos, you will need to do that first, you do not 
need to have the debian repositories)

8)Get scim to switch typing to Japanese with  'Ctrl+Space'
  1)(No known instructions online)
  2)Inactivate xandros repositories
     1.Press Alt+Ctrl+t to open a console.
     2.Open a text editor to edit  '/etc/apt/sources.list'
      1. type <sudo kwrite /etc/apt/sources.list>
     3.Put '#' in front of each line except the first two (asus repositories)
    4.Save the file
    5.Close the text editor
  3)Check that there are no conflicts when installing 'scim*'
    1.In the console type <sudo apt-get -s install scim*>
    2.Click Enter
    3.Check that no major conflicts/ deletions would occur
    4.There is a list of Suggested packages, take a note of them:scim-uim scim-hangul  
      scim-m17n scim-prime scim-anthy scim-skk scim-canna scim-tables-additional 
      scim-tables-ja scim-tables-ko
  4)Install/update 'scim' and its dependent packages
    1. type <sudo apt-get install scim*>
    2. Click Enter
    3.Type 'y' answering whether to install 
  5)Activate xandros repositories
    1.Press Alt+Ctrl+t to open a console.
    2.Open a text editor to edit  '/etc/apt/sources.list'
      1. type <sudo kwrite /etc/apt/sources.list>
    3.Remove '#' in front of each xandros repository line (starts with 'deb'), 
      (do not activate debian repositories, unless currently needed)
    4.Save the file
    5.Close the text editor
  6) Install the suggested packages
    1.Type <sudo apt-get update>
    2.Test the suggested packages
      1. In the console type <sudo apt-get -s install scim-uim scim-m17n scim-prime 
         scim-anthy scim-skk scim-canna>
    3.Install the suggested packages
      1. If no conflicts or deletions type                                                                  
      <sudo apt-get install scim-uim scim-hangul scim-m17n scim-prime scim-anthy scim-skk 
      scim-canna>
      2. Type 'y' when prompted
    4.Test the suggested packages
      1. Type <sudo apt-get -s install scim-tables-additional scim-tables-ja>
    5.Install the suggested packages
      1. If no conflicts or deletions type                                                                          
      <sudo apt-get install scim-tables-additional scim-tables-ja scim-tables-ko>
      2. Type 'y' when prompted
    6. Close the console
  7) Set Japanese as Language of SCIM choice
    1. The first time Ctrl+Space is used, click on the text in the field which appears in 
       the bottom right corner.
    2.In the menue that shows up, click on 'Japanese'
    3.In the sub-menue that shows up click on the top choice ('Anthy')
    steps 1-3 are needed only once
    4.When typing in Japanese, use Space to choose the right kanji
    5.Use Ctrl+Space to get back to typing in latin letters.
  8) Fix Firefox after working on scim
    1.Instructions are at http://wiki.eeeuser.com/bugfixes:updatebreaksfirefox


Enjoy your eeePC in Japanese and keep putting info in the wiki, I need all the help I can get    :-)

FanFan101    :-)