ibook translation

I have published an ibook successfully with ibooks author on the ibook store. I am now doing several transations, German, French , Italian ec of this book.

I undertand that each translation will need a new ISBN number and will need to be republished on the ibook store as though it was a new book.

So far so good.

What I want to do is to use iTunes Producer, and just change the ISBN number and the assets and then republish the translations.

However I am not able to edit the ISBN number in iTunes producer or save it as a different file.

Nor can I export the data of the .itmsp file from iTunes Producer into another format so I can edit these items.

How can I easily publish all my translations using the same Metadata?