Adobe AIR for Android - GPU Mode - Bitmap Auto-Smoothing Issue

Hi everyone

I'm having a bit of an issue with the AS3 bitmap object. I'm currently developing an 8-bit style pixel game for AIR for Android.
This game is being developed at a very low resolution and is being scaled up to maintain the charm of an old retro game.
One of the methods I'm using is drawing pixels directly to bitmap objects and scaling the object up to create the old look.

When testing on a mobile device, this works beautifully when you set the rendering method to Direct but when you change
the render method to GPU the visuals go all blurry and anti-aliased (it's as if the bitmap is being smoothed out). The mini map
for example is rendered using the setPixel method and then scaled up 9 times. Looks great on my PC but once I export it to my phone
it looks absolutely awful! This is no good as I want to keep the clean, solid pixel look to maintain the the old 8-bit feel and obviously
I'd like to stick to GPU mode due to it's speed.

Like I said, this only happens once you test on a mobile device in GPU mode - it doesn't do it on my main desktop machine or
in Direct mode. I already have the stage quality set to low and I've tried setting the bitmap's smoothing property to false but
it does nothing.

Does anyone have any suggestions as to how I can get around this?