Thanks guys for the "embedded" hints in this thread. I had ignored the apprentice tools because he is not clear enough about the inclusion of a tool quite useful on official kepubs. (That inclusion is just explained in the comments!!!)
So I suppose I will have to try it. Just because I love playing...
I have never used the apprentice's tools, because quite long ago I found another set (look for epubee) which, at least in my case, has always worked like a charm with my drm epubs and pdfs. And of course I've never updated my PC ADE to version 2.x (am I on 1.8.something?) as I only use that program to download my hated DRMed brand new adquired books... If something works, do not try to fix it.
So I finish with a great
. Never go to bed without having learnt something new (Spanish idiom).