I had installed iRite before
but then I had started over from scratch: deleted iRite via extension manager, deleted the wincache, installed html editor, deleted all connections to iRite (which very often are *NOT* converted or deleted as the instructiuons suggest), deleted the WA-irite folder. I even reversed the iRite entities into a texterea.
Only then I setup HTML Editor via Insert - Webassist - HTML Editor and started with Site Settings. From there I immediately selected advanced.
I really have no idea what I might have omitted, since I have tried any possible combination of settings. Most of them with clean files.
Is there a way of setting it up without this (in my case) obviously non-working interface, as my colleague suggests?