Despite the properties files being in the source directory, Maven was building it a different one called main.java.the_path_where_the_file_really_is. For the moment and while I try to figure out how to make Maven place the file in the correct place I have modified the faces-config.xml file to include the path Maven left the file:
main.java.com.daslernen.bundles.messages
And now works like a charm :)