Android : Android AccountAuthenticatorActivity finish

I have implemented a accountactivity to add a account to the system settings. The activity is opend froma a app over the AccountManager addAccount method. I fill out my form, submit and login my user. All works fine. But if kill my app over the recent apps, my app is also running and never shutdown. I found out, that is has to do with these lines:

setResult(RESULT_OK, _intent);
setAccountAuthenticatorResult(_intent.getExtras());
finish();

If i switch setAccountAuthenticationResult() with finish() the app can be killed, but i get a OperationCanceledException in the addAccount result.

Any idea why my app isnt killed and how to implement to shutdown the authenticatoractivity?