[office 2010] unattended installation including MUI

Hello,

I am trying to deploy Office 2010 including MUI.
I created a config.xml file. This is the content of the file:

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<Configuration Product="ProPlus">

<Display Level="full" CompletionNotice="yes" SuppressModal="no" AcceptEula="yes" />
<Logging Type="standard" Path="c:\" Template="Microsoft Office Professional Plus Setup.txt" />
<USERNAME Value="Customer" />
<COMPANYNAME Value="MyCompany" />
<INSTALLLOCATION Value="%programfiles%\Microsoft Office" /> -->
      <!-- <LIS CACHEACTION="CacheOnly" /> -->
      <!-- <LIS SOURCELIST="\\server1\share\Office;\\server2\share\Office" /> -->
      <!-- <DistributionPoint Location="\\server\share\Office" /> -->
      <!-- <OptionState Id="OptionID" State="absent" Children="force" /> -->
      <!-- <Setting Id="SETUP_REBOOT" Value="IfNeeded" /> -->
<AddLanguage Id="de-de" ShellTransform="Yes" />
<AddLanguage Id="en-us" />
<!-- <Command Path="%windir%\system32\msiexec.exe" Args="/i \\server\share\my.msi" QuietArg="/q" ChainPosition="after" Execute="install" /> -->

</Configuration>
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I have placed the EN-US folder from the MUI dvd into the Office 2010 CD/DVD.
Then I run the command: setup.exe /config config.xml

The installation does not start stating that there is a failure installing the language pack:

 
Also starting the msi inside the language pack does not work, I have to use the setup.exe.

- Is there a way to install the language interface from the MUI dvd/cd with an unattended answer file?
- Can I just place the language interface folders inside the Office dvd/cd and add the language to the config.xml?
- Are there any known issues with installing language packs for Office 2010?