why don't u make another sheet cake of whatever size pan u have or make two and just place the book cake on top
If you are wanting to put the book pan on top of another cake you need to have the bottom cake bigger than the book cake. You would need to put your book cake on a board of some sort and make sure you are putting supports in the big cake under where you will be setting your book cake. You are just doing a stacked cake...no different than doing a wedding cake or any tiered cake...I would use a sheet pan ( 11x1
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Make a one layer sheet cake larger than the book. Decorate both cakes separately, then place some dowels into the sheet cake to support the book cake. Put the book cake on top and add a border. Using the dowels will make it so the book cake can be removed and cut separately.
Good luck! 
Duplicate request, please see also:
http://forum.cakecentral.com/cake-decorating-ftopict-325383-.html
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