Yeah, the keyboard that is displayed on the emulator is (for now at least) equivalent to the hardware keyboard on the device. Maybe that will change on the new update when it reaches us, as I believe there is supposed to be support for an on-screen keyboard.
Sorry I can't help with solving your problem but I assume that the entire keyboard is lit up by one light source (I've not taken too many phones to pieces
) so it might be impossible. As we've got no on-screen keyboard yet I'm sure there must be a way of highlighting a keypress on it when it finally appears