Regarding the 'right' way to represent vertical space in epub files: It is pretty clear that using a p element containing only is an ugly hack, and is the wrong thing to do, in terms of web standards (see for instance the discussion at
http://stackoverflow.com/questions/1...-editor-or-not ). The right thing is certainly to use CSS styles to add a margin of the appropriate size. I'd hope that the implementers of Scrivener etc. will get round to fixing their program at some point, to do the right thing. I don't feel especially proud of having changed Freda to fit in with their broken interpretation of the xhtml standard ;-)