I might as well reveal the hax I am currently using to solve my problem. On the "pre-logged in" activities, I have set this in the manifest:
android:noHistory="true"
Then in each activity I have this code:
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
Intent intent = new Intent(MyActivity.this, ParentActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_NO_ANIMATION);
startActivity(intent);
return super.onKeyDown(keyCode, event);
}
return super.onKeyDown(keyCode, event);
}
The FLAG_ACTIVITY_NO_ANIMATION only works on phones with API level 5 or higher, but what it does is that instead on the "open new activity"-animation, the "going back to previous activity"-animation is played (atleast on the droid and nexus). This prevents the confusing appearence that a new activity is started when the user presses the back-button.
This solution is not perfect. On phones with a API-level lower then 5 the animations becomes incorrect. Also, it is not super neat and requires more code then I prefer. Still, it works...