Heh, I found
one soft, which does PDF to ePub and manages to preserve the ToC/bookmarks, but unfortunately it also managed to mangle the lines of the book and order of chapters..
edit: not so fast, Tonttu: I tried without the option "Paragraph check" and that prevented it from mangling shit up. Of course the lines look silly in a wide resolution, BUT it's perfectly fine for my small-ass Kindle Touch! Brilliant!
Well the mangled chapters are still a problem, but I have to take a look at Sigil for a possible easy fix..
edit2: ok it was a case of unzipping the epub and looking at the structure: chapter one had been split and the end part had been put under a non-referenced bookmark. Also content.opf had the first itemref as linear="no" and one idref was missing .html extension. After fixing those, everything is fine.