UISegmentedControl unselect segment by pressing it again

How can one unselect a given segment in a UISegmented control, by pressing the same segment again?

E.g. Press segment 0, it becomes selected and remains highlighted. Press segment 0 again and it becomes unselected and unhighlighted.

The control only fires UIControlEventValueChanged events. Other events don't seem to work with it.

There is a property 'momentary' which when set to YES almost allows the above behavior, excepting that highlighting is only momentary. When momentary=YES pressing the same segment twice results in two UIControlEventValueChanged events, but when momentary=NO only the first press of a given segment results in a UIControlEventValueChanged event being fired. I.e. subsequent presses on the same segment will not fire the UIControlEventValueChanged event.