Seekbar in Options Menu

I'm trying to add a seekbar item to my options menu, but all I get is a panel with my title for the text. In my main activity I'm doing this:

@Override
public boolean onCreateOptionsMenu(Menu menu)
{
    getSupportMenuInflater().inflate(R.menu.activity_main, menu);
    return true;
}

And here is my activity_main.xml:

<menu xmlns:android="http://schemas.android.com/apk/res/android" >

<item
    android:id="@+id/transparency_seekbar"
    android:showAsAction="never"
    android:title="test"
    android:actionViewClass="android.widget.SeekBar"/>

</menu>

So far as I know this isn't possible to customize the options-menu, you might want to override the menu button press and create it by yourself in a layout. The follow function handles the menu-press.

@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    if ( keyCode == KeyEvent.KEYCODE_MENU ) {
        //Put the code for an action menu from the top here
        return true;
    }
    return super.onKeyDown(keyCode, event);
}