UI2 was designed to be used by a remote, such as a Windows MCE remote, or a mouse, or a Fiire Chief.
In all cases, there is a back button which can get you out. (f2 on the keyboard)
For touch screens, use UI1.
I would suggest using an external orbiter as well, get an unused PDA, or a Nokia N800 or an old tablet PC...it will work better....failing that, just use UI1 on your on-screen display.