Same problem for me. I've searched lots of threads here, but no useful answer.
I would like to have the pdf's
existing TOC to be converted to the TOC in epub/mobi (or whatever). The only way I found so far is somehow "deriving" the TOC backwards from calibre's conversion results, using html tags/classes.
So I would like to ask for help again: is there a way to get the pdf's
existing TOC to be converted to the TOC in epub/mobi?