anchor.diff:                                      Error
                               ;   {ok, ok} ->
                                       TokenID = oauth1_credentials:get_id(Token),
  -                                    IsCallbackConfirmed = false,
  -                                    {ok, {TokenID, IsCallbackConfirmed}}
  +                                    Callback =
  +                                        oauth1_callback:cons( TokenID
  +                                                            , CallbackURI
  +                                                            ),
  +                                    case oauth1_callback:store(Callback)
  +                                    of  {error, _}=Error ->
  +                                            Error
  +                                    ;   {ok, ok} ->
  +                                            IsCallbackConfirmed = false,
  +                                            {ok, {TokenID, IsCallbackConfirmed}}
  +                                    end
                               end
                       ;   {error, _}=Error ->
                               Error
  
positive.code: 
                  , token                = none
                  , verifier             = none
                  , callback             = {some, ClientCallbackURI}
                  },
              SigComputed       = oauth1_signature:cons(SigArgs),
              SigComputedDigest = oauth1_signature:get_digest(SigComputed),
  
negative.code:     , timestamp           = Timestamp
      , nonce               = Nonce
  
      , client_callback_uri = CallbackURI
      , host                = Host
      }
  ) ->
  