Here is a quick script I used to create a GPI which you could map a keyboard shortcut to. It will get the timer value and add or subtract 30 seconds to it while on air.
Get the countdown clock widget from engine, get the TimerValue and either add or subtract 30000 milliseconds.
dim Clock as xpBaseWidget
Engine.GetWidgetByName("CountdownClock",Clock)
Clock.TimerValue = Clock.TimerValue + 30000
Use the same thing for subtracting.
Hope this helps.
Mike
#XPression