2 problems using statemachine with scxml

[Fakeleather]

Hi, I'm building simple voice app using QScxmlStateMachine with scxml file and qml(mainly),
there's 2 stuck points matching voice interface concept.

1. I'm looking for the event handling method for each state.
   for example, let's say that there's a state having some events to transit to other state.
   I want to manage the event if it's not processed by the current state and raise errorEvent.
   as I'm testing, the wrong event(if I say) seems just dropped or queued without notification.
   how can I handle that..?

2. how can I implement "back" command efficiently which is literally backing to the previous state?
   for now, there seems only one way which draws transition tag for each states - conditioning by previous state!
   Could there be any functions to use like goToState(target) so that I can make state stack and pop the previous one and use..?