Unable to create Keynote Keynote in 2048x1536 px. for iPad w/ retina display. This option doesn't appear under "Slide Size". Keynote 5.1.1.

I have tried creating a Keynote document for iPad 3 but 2048x1536 does not appear under thre options for slide size.

The biggest is 1920x1080. I have updated all software and Keynote is on the latest version 5.1.1. I have tried on two different machines but I get the same issue.

Any ideas what it could be?

Any help appreciated.

Thanks.