Why can I view iWork 9 files in Briefcase?
Apple changed the file formats used by iWork in the new version (iWork ’09). Briefcase use’s the iPhone’s built-in support for viewing iWork files. Because of that, we cannot directly address this problem. We have filed a request with Apple to update iWork file support in the next iPhone OS upgrade. In the mean time, you can save your files out of iWork using the old iWork ’08 format. Remeber to also select “Include preview in document” for best results.