What is the code flow for using AudioTrack to play audio on device after startBluetoothSco is called?

Question

I am connecting a mobile device with Android OS 4.1 to a Bluetooth device (device class = 1792), using BluetoothSco to route audio (voice). I've setup a BluetoothSocket using createRfcommSocketToServiceRecord successfully.

My settings:

Using AudioRecord and AudioTrack with frequency = 8000, MediaRecorder.AudioSource.MIC as the source for AudioRecord , AudioManager.STREAM_VOICE_CALL for the AudioTrack, and trying both MODE_IN_COMMUNICATION and MODE_IN_CALL for the AudioManager mode.

without success. I don't get audio on my device.

My questions:

1. Should I use MODE_IN_COMMUNICATION or MODE_IN_CALL?
2. Need I switch to MODE_NORMAL or other mode in order to play on device?
3. Can you suggest a code flow to make SCO audio play on a device?
4. Can you point out some working code to review?

Notes:

1. The "Media audio" profile (A2DP) is disabled on the device - only "Call audio" profile (HFP) is enabled.

Will gladly share some code, yet given existing SO Q&As it will probably look the same.

Regards.