Save a document or book as Adobe PDF

The FM9 user manual talks a lot more about saving as PDF (http://help.adobe.com/en_US/FrameMaker/9.0/Using/WSC499FA78-8A12-4222-A5D9-D5DC41DAA0C9.html#top)

Still, the FM9 manual describes my problem only a little.

When I save my file as a PDF with RGB colors, my A4 size pages get converted to US letter size pages. So because the FM9 manual says "The RGB route does not support bigger page sizes but this is not a limitation in the CMYK route," I saved my file with CMYK colors and the page size problem disappears! But then my colors are all wrong. Can I get an Adobe PDF Creation Add-On to support larger page sizes with RGB color?