Lightroom 4.1 Question

I’ve already published a Standard Landscape Harcover Image Wrapped Book, but I want to add a Soft cover version and maybe some additional sizes to the same book. I know how to change the settings and layout in Lightroom, just want to know how to upload it without it creating a new book, I want it added to the same book.

Here’s a link to the book I want to add sizes to

http://www.blurb.com/bookstore/detail/3429695

Thanks

Glenn