Keynote for IOS 1.7 apparently does not currently allow you to create or import "smart builds" of multiple objects such as those created in Keynote 09 for Mac. When you import a presentation with a smart build into Keynote on an IOS device you will see an error message saying the smart build was not imported. You CAN do basic in and out builds of SINGLE objects such as fade in and fade out.
I, too, am very disappointed in not being able to build an image slide show since I consider this a basic object build feature. I would hope that correcting this deficiency is a priority for updates.
The only possible work around I can think of is to create images of the objects you want to cycle through and bring them into a movie editor such as IMovie to create a slideshow Quicktime video, then insert a single .mov file into your presentation. That will import and play on IOS Keynote.