Sign Text to Speech in the Background

Do you have any idea about how to read ebooks alound in the background, thanks.

I use coolreader and a TTS engine to listen to books. Feed a text book, it is read aloud.

The problem comes when I switch to another app, like waze, or facebook, or anyother. The reading is interrupted because either the tts engine or the ebook reader is terminated - closed by android

What I have tried:
- installing auto memory manager app to increase the omm app priority for both coolreader and the tts engine. Doesn´t work

- installing fbreader and tts plugin + for fbreader, which specifically says it is kept alive in the background. Doesn´t work
=> beats =>
Hands Down!
I want hardware buttons back ....