@al3bsi: I can't really test that, since I have no idea how arabic is supposed to look like
. But if you say that the font used by the reader supports Arabic and it works, then a crude workaround would be to *copy* the four Serif_*.ttf fonts over the four Sans_*.ttf fonts, in order to use the Serif fonts nearly everywhere (and especially in the book list ^^). AFAIK, Arabic doesn't really have the same notion of Sans/Serif as latin languages anyway...