How can we update the system wallpaper in an Android 1.6 service after changing it with setWallpaper()?

Question

We are doing a simple service that changes the wallpaper when the phone (an SE xperia x10 mini) is tilted. So basically the code "almost" works - the problem is that the system does not appear to know that the system wallpaper have been changed or does not do anything about it. Starting and closing another app manually appears to enforce an update.

In an event call the following is done: getApplicationContext().setWallpaper(pWallOne);

Is there some way of telling the android system to update the graphics or to do some cheap trick that forces it to? Any help or tip would be very much appreciated!!