Why doesn't Google's MapView show traffic outside of the USA on Android 2.2?

I'm have the Google MapView embedded in an Android app I'm writing and I want it to show the traffic layer of data.

I can do this using:-

mapView.setTraffic(true);

And I've even made sure I use the...

mapView.invalidate();

..trick to work around a bug.

The app displays traffic data in the USA only for some reason! It won't display any in other countries. I have other apps using the Google MapView and they do show traffic in my home city (Sheffield, UK).

Does anyone know how I can make it display non-USA traffic please?

(I have the app running on an HTC Desire with Android v2.2).

EDIT: I've run the app in an emulator using Android 2.3.3 and the traffic IS displayed outside of the USA but in an Android 2.2 emulator it doesn't sho开发者_运维技巧w.

Live traffic data is available in major cities in the United States, France, Britain, Australia, and Canada, with new cities and countries frequently added

http://maps.google.com/support/bin/answer.py?answer=61454