Trying to sync books already in iBooks back to iTunes with no luck
I'm a new iPad owner, loving iBooks, it's wonderful. I previously owned a Sony eBook reader, and had several .epub books, which I put in my iBooks library.
To do this I would email my .epub book files to myself, and then when I opened my email in my iPad and clicked on the file, it would ask if I wanted to open it in iBooks, and I would do that.
Well that's great, I now have all my books on my iPad in iBooks, BUT, I want to back them up in iTunes, and when I plug my iPad into my computer and sync the books, they don't show up in iTunes.
Can someone tell me how I can fix this, or is it because I didn't purchase these books thru iTunes, that it won't allow me to store them in iTunes. I'm worried that if something would happen to my iPad, they won't be backed up and I don't want to have to go to the bother of mailing myself all these files again. Thanks for any help you can give me.