Something strange just happened. Yesterday I managed to put several books into the "Docs"-category and they didn't even show a "Personal"-banner:
http://imgur.com/a/ytAaw
Today the PDOC-setting is completely ignored. I can't even put mobi-files in the "Docs"-category any longer. I'm not sure if I yesterday changed the output-settings from
mobi (old) to
mobi (both) and back afterwards, I don't remember.
Fact is, as you can see in the screenshots above, that I managed to put files in the "Docs"-category, without a banner, on firmware 5.4.3.2 and today it doesn't even work with Non-KF8-mobi-files.