iBooks two page spread for children's picture ebooks

Hi,

I am creating a children's ebook for iBooks and I'd like to get the following result (taken from Peppa Pig: Tiny Creatures, published on iTunes for iBooks):

The final picture ebook should have a gutter/seam in the center, 2 page spread and pages that stack when flipped.

I saw in this post that iBooks Author can't do that and we should use use Pages instead, exporting the book as an ePub to iTunes.

But how can I do this in practice with Pages? I see that Pages doesn't export the file to ePub if certain layout features are enabled and that we should follow a strict procedure to create an ePub with Pages, as described in the "ePub Best Practices".

Now, if I follow the ePub Best Practices template, I come out with a pretty dull design, good only for novels or similar.

In particular, how can I spread a picture across two pages in Pages and get that rendered by iBooks?

For example, if I want a picture to spread across 2 pages (as shown in the picture above), do I need to place the image in a "single" landscape page in Pages, and that will be spread across 2 pages when viewed in iBooks? Or should I choose a spread layout in Pages and that will be correctly picked up by iBooks, which will also add the seam effect in the middle of the book?

Thanks.