android: audiotrack to voice call

Question

hi all, i'm trying to play a sample to voice call uplink stream...

int minSize =AudioTrack.getMinBufferSize( 44100, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT ); final AudioTrack track = new AudioTrack( AudioManager.STREAM_VOICE_CALL, 44100, AudioFormat.CHANNEL_CONFIGURATION_MONO, AudioFormat.ENCODING_PCM_16BIT, minSize, AudioTrack.MODE_STREAM); track.play();

and then send data to the stream...but it does not play to the calling phone...

is it maybe a problem with AudioManager, but how may i configure the routing process?

thanks in advance, regards