I figured out how to do it. Haven't found it anywher in the ccp UI, but ccp generated an 'ExceptionConfig' file in the Exception directory.
In that file I changed the following:
<Argument name="LANG_LIST">[installLanguage]</Argument>
to
<Argument name="LANG_LIST">en_US,nl_NL,fr_FR,de_DE</Argument>
After that all the specified languages get installed and Acrobat appears in the language of the logged on user.