I was having a problem with getting uitextinput to behave correctly so I deployed your demo scene (ui layout demo) to a window phone 8 device for testing, still same problem.
Scenario :
When I tap the uitextinput, the cursor/touchkeyboard appears. If I tap out of the uitexinput control and retap the uitextinput, the touchkeyboard appears however I could not enter text anymore. It works in editor and pc/mac standalone build, but not in window phone 8 build.
Version tested : 2.30 and 2.33