Spread on Large Hardcover Dust Jacket, what appears on the spine?

I'm designing a large hardcover book and I've created an outer spread across the dust jacket. I was hoping that the photograph would print across the spine but on-screen there seems to be no allowance for this (i.e. the width of the spread is exactly two page widths with nothing extra allowed for the width of the spine).

So, simple question - how does the spine of the printed book appear when a photo is spread across the dust jacket?

Thanks,

Graham

P.S. this thread http://discussions.apple.com/thread.jspa?messageID=6734031&#6734031 mentions that the title is printed on the spine but doesn't say whether it appears over the photograph if the outer cover is configured as a spread...