Yessh, some progress: 770/Plucker works and "works" (!) but only (=?) with those couple of the model eBooks introduced at the Plucker site. Unfortunately I did my first tries with my old eBooks (same .pdb extention), which 770/Plucker seems to be unable to open. So - "wrong" subformats should be translated to 770/Plucker-format, I suppose, but how.
BTW: maemo's Application Cataloque states now firmly that its even "ready" applications (and corresponding info) are for developers only, not for any kind of
"end-using".
And let's remember that 770 Apps Installer declares before the actual installation that the function is "for developers only"!!!!