Android : Android xml animation

I'm trying to create an anaimation and I CANT use any code for it. why you ask? its for a widget, that means that I can set visibilty for views but not animate them.

so this is what I have and I cant figure out why I get blank insted of a animation with a bitmap:

<scale
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:duration="800"
    android:fromXScale="1"
    android:fromYScale="1"
    android:pivotX="50%"
    android:pivotY="50%"
    android:toXScale="1.2"
    android:toYScale="1.2"
    android:repeatCount="infinite"
    android:repeatMode="reverse">

<bitmap android:src="@drawable/icon_enc" ></bitmap>
</scale>

so I want to have a ImageView with this as background.

why Im getting a black background? (and so is the preview);

thanx , Yakir.