Drawables with Layers - resizing one of them - Android

I want to combine 2 Drawables into one, as can be seen from my layout: http://i.imgur.com/tOEiO.jpg

I want to use drawable as the background of a TextView object. I tried like this:

            Drawable[] layers = new Drawable[2];
            layers[0] = new ColorDrawable(0xffff0000);
            layers[1] = resources.getDrawable(android.R.drawable.ic_btn_speak_now);
            LayerDrawable layerDrawable = new LayerDrawable(layers);
            setBackgroundDrawable(layerDrawable);

Unfortunately, with this code, Drawable from layer 1 scales to the size of the TextView object.

Now my question is:

How can I get Dalvik to position layer 1 always vertically centered and horizontally right, and not scale it to the size of another layer? (e.g. in my layout).

Many thanks!