Android :: Views In Custom Compound Component Not Inflated

I have made a Custom Component in XML, consisting of a button with an imageview stacked on top of it:

<myapp.widget.ClearableCaptionedButton
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<Button
android:id="@+id/ccbutton_button"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical|left"
android:textAppearance="?android:attr/textAppearanceMedium"
android:background="@android:drawable/edit_text"/>
<ImageView
android:id="@+id/ccbutton_clear"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginRight="5dip"
android:layout_alignRight="@id/ccbutton_button"
android:layout_alignTop="@id/ccbutton_button"
android:layout_alignBottom="@id/ccbutton_button"/>
</myapp.widget.ClearableCaptionedButton>

Extract of java source code:
public class ClearableCaptionedButton extends RelativeLayout implements OnClickListener {
...
public ClearableCaptionedButton(Context context, AttributeSet attrs) { super(context, attrs);
// some stuff that works fine
} ..
protected void onFinishInflate() { super.onFinishInflate();
mButton = (Button) findViewById(R.id.ccbutton_button);
mClear = (ImageView) findViewById(R.id.ccbutton_clear);
mButton.setText(""); // error here: mButton == null
}

My problem is similar to this one. When I try to find the views inside the custom compound, findViewById returns null. But, as you can see, i already added super(context, attrs); to the constructor. I am using the custom component directly in xml layout, like this:

<LinearLayout>
<!-- some stuff -->
<myapp.widget.ClearableCaptionedButton
android:layout_width="fill_parent"
android:layout_height="wrap_content"
app:caption="to"/>
</LinearLayout>