Pass custom user data book fields to other projects

I have created some custom "user data" properties in a book.  I would like to push these properties to older projects.  I tried copy/paste new book to old project and tried using a project macro to add to old project.  Both ways failed in passing the custom user data fields to the new books in the old project. 

Does anyone have any other ideas?  My alternative I can think of is to manually create these custom fields in each old project.

Thanks,

Zac

SolidworksElectrical