Okay, I'm willing to move with the times, although I don't use epub3.
So you're saying you include the com.apple.ibooks.display-options.xml, and also prefix="rendition:
http://www.idpf.org/vocab/rendition/# ibooks: http://vocabulary.itunes.apple.com/rdf/ibooks/vocabulary-extensions-1.0/"
Where and how do you add the latter? I'm new to all of this, so please explain to me as you would a twelve year old.