[AC-2940] Android: Density-specific backgroundImage is being ignored

I'm trying to use a backgroundImage property on several buttons and views, and have each as a set of density specific images (/Resources/android/images/res-*dpi/image.png) as well as a default /Resouces/images/image.png. In SDK 1.7.5 this works fine but if I use any version higher that this the density images are ignored and the default is always used.

var win = Titanium.UI.createWindow({
	backgroundColor: '#604040',
	layout: 'vertical'
});

var image = Ti.UI.createImageView({
	image: '/images/test.png',
	top: '20dp',
	width: '108dp',
	height: '84dp'
});

var button = Ti.UI.createButton({
	backgroundImage: '/images/test.png',
	top: '20dp',
	width: '108dp',
	height: '84dp'
});

var view = Ti.UI.createView({
	backgroundImage: '/images/test.png',
	top: '20dp',
	width: '108dp',
	height: '84dp'
});

win.add(image);
win.add(button);
win.add(view);

win.open();

Running the attached project (above) on 1.7.5 shows me the same 3 *DPI images as expected, but anything above that shows the top image properly (it uses an image property), and the bottom 2 show the 'default' image (these use backgroundImage). I don't think I'm doing anything special, and I've tried every combination of OS, Javascript runtime, Android SDK, Ti SDK, emulator size, fastdev etc I can think of. The earliest CI build I've tried is 1.7.6.v2011120913042, also 1.8.0.1.RC1 and many 1.8/1.9 CI builds up to 1.9.0.v20111214004742.