Books don't appear on both iPads

My wife & I have an iPad and we use the same AppleID to buy books and Apps. (we have different iCloud ID's)

This worked well until iOS7.

I can buy my books without problem (my AppleID and iCloud ID are the same) but my wife can no longer buy books. She can log into the iBookstore with my AppleID but when trying to buy a book, nothing happens.

The other problem is that if I bought a book, it would automatically also show up on her iPad. Now, no longer.

We want to be able to share books, the same way as people can share a "hard copy" book.

What is happening??? This iCloud thing is really screwed up