Media kind is greyed out

I purchased an album on iTunes and want to change the Media kind of the digital booklet so I can sync it to my device as in http://support.apple.com/kb/HT4194. The media kind button is greyed out. It is a PDF file but it doesn't show up under iBooks. Does anyone know a work around. It's frustrating because adobe won't open the PDF either and their article is out of date.