How to answer incoming call? telephone.answer not working

[jellinek]

I'm using 1.4.1 final on an E50.

I'd like to use telephone.incoming_call() and telephone.answer() to answer an incoming call. The documentation says:

incoming call()
Wait for incoming call, returns immediately. If a call arrives, answer can be called to answer the call. Without the invocation of function incoming call, the function answer has no effect.

answer()
Answers an incoming call - see also incoming call.

My app looks like this

import appuifw
import e32
import telephone

STATES = {telephone.EStatusUnknown:          "unknown",
          telephone.EStatusIdle:             "idle",
          telephone.EStatusDialling:         "dialing",
          telephone.EStatusRinging:          "ringing",
          telephone.EStatusAnswering:        "answering",
          telephone.EStatusConnecting:       "connecting",
          telephone.EStatusConnected:        "connected",
          telephone.EStatusReconnectPending: "reconnect pending",
          telephone.EStatusDisconnecting:    "disconnecting",
          telephone.EStatusHold:             "hold",
          telephone.EStatusTransferring:     "transferring",
          telephone.EStatusTransferAlerting: "transfer alerting"};

def handleCall((callState, number)):
    print "callState = "+STATES[callState]

    if callState == telephone.EStatusRinging:
      if number == "":
        print "incoming call"
      else:
        print "call from "+number
      telephone.answer()
    elif callState == telephone.EStatusAnswering:
      print "hanging up"
      telephone.hang_up()
    elif callState == telephone.EStatusDisconnecting:
      print "hung up"

def quit():
    app_lock.signal()

appuifw.app.exit_key_handler = quit

app_lock=e32.Ao_lock()

old_title = appuifw.app.title
appuifw.app.title = u"Incoming"

telephone.incoming_call()
telephone.call_state(handleCall)

print "waiting for a call"

app_lock.wait()
appuifw.app.title = old_title

When a call comes in I see this in the console:

waiting for a call
callState = ringing
incoming call

(caller hangs up after 3 rings - the app did not answer the call)

callState = disconnecting
hung up
callState = idle

The call to telephone.answer() seems to have no effect. I have also tried calling it in other spots: before and after the call to telephone.call_state() and in the ringing case in handleCall. Has anyone else gotten telephone.answer() (or incoming_call()) to work?

Thanks.