...As the software saves the book as in a proprietary XML format, I took matters in my own hands, reverse engineered it and created an simple java application that provides that missing functionality.
Screenshots available on: http://redgreenblue.squarespace.com/cewe-photoalbum-exporter/
Note: You need to have Java Runtime (JRE >= 1.6) installed to be able to run this program.
Check the "Files" section for binaries for Windows, OS X or Linux, or you can build the newest version yourself by cloning the git repo and building the jar with gradle (see "how_to_build.txt").