How do one access the numeric keypad during a call so that you can type in numbers, for example if you need to type in 100 during a call to check voicemail?
It should... Icon in the bottom-left of the screen should bring up the numerical pad when on a call; if it doesn't respond to input from there, there is something wrong. Assuming it's the same as the Desire, there's a proximity sensor that should switch off the screen as you bring it to your ear. Conversely it takes a second or so for the screen to come up when you lower the phone.