Originally Posted by 3d0g
My guess is kobo has intentionally chosen to deliver specific fonts to insure an optimal experience on their eReader. As it's not a "bug" but a concious design choice, I wouldn't hold your breath about it getting "fixed".
So then users of a Kobo are not allowed to have true styles and are stuck with the simulated styles. Is that really such a wise choice? It's because of the way ADE handles fonts that a lot of eBooks are coming with embedded fonts. ADE uses one font and simulates bold and italic. The italic looks awful. If the publisher has decided to make the books look better (see the Stig Larsson ePub for example) then the users of Kobo get shafted.