Communications

I have problems witth the Toxbox::Communications:

I have set up an Android app to handle both, DeviceEvents and AppEvents which is running on a Nexus4 and is connected via adb forward to the Connect IQ Device Simulator running my Widget, with "Communications" permissions set. The connection is established instantaneous and seems pretty reliable. Sending from AndroidApp to IQ Simulator via "mConnectIQ.sendMessage()" works, but the other way, sending data from watch to Android App is not working at all.

var listener = new CommSendListener();
var testString = "test";
Comm.transmit( testString, null, listener );

with CommSendListener defined as
class CommSendListener extends Comm.ConnectionListener {
function onComplete() {
Sys.println("transmit complete");
}
function onError() {
Sys.println("transmit failed");
}
}

does not even call the onError callback. Is this not yet implemented or what am I missing here?

Thanks a lot!