Post to member's Facebook for free ebook

Hi, I am not sure this plug-in can do this but here is what I am trying to do: I have an Ebook that I want to give free IF a member posts on their own personal wall that they are reading the book.

I have seen websites ask for permission to post to your wall---this is what I want to do, but if they refuse, then they don't get to read the ebook. Is there a way to do this with Ultimate Facebook or other?
Thanks
Geo