ibooks help

Ok here is my problem,

i have a ton of books in ibooks.
and some belong to a series like alex cross by james patterson.
so in itunes i rename all the books so they appear in order so it is easier to know which book comes next.

well i did that in iTunes rename the books and synced my iPad, and the books do not change. they are still named differently on my ioad, and on my mac, they are named to what i chose.

how do i fix this?

thanks