I am using boost::statechart. Instead of simple_state , using boost::statechart::state.
Now i am able to access the state_machine member variable. but when i am using custom::reaction or mpl::list it throught error. 
Code Snippet:

struct NotReady : StateBase< NotReady, TopState >
{
  //typedef NotReadyStateList reactions;
  NotReady (my_context ctx) : my_base( ctx ){
 outermost_context().maxPairedDevices = 3;
 cout << outermost_context().maxPairedDevices << endl;
  }

  template< class MostDerived >
  sc::result react( const PairingBaseEvents< MostDerived > & );
public:
  typedef sc::custom_reaction< StartEvent > reactions;
};

Error:
ndefined reference to `boost::statechart::detail::safe_reaction_result NotReady::react<StartEvent>(PairingBaseEvents<StartEvent> const&)'

regards
Rahul Baruah