splitActionBarWhenNarrow means that it will be split, not moved anywhere and only when narrow. Thus if you are in portrait or wide screen the menu options will always appear at the top. You cannot force ActionBar to be drawn at the bottom. Instead you might want to disable ActionBar completely and putting your own custom view at the bottom with ImageButtons with actionButtonStyle
<style name="NoActionBar" parent="@android:style/Theme.Holo.Light">
<item name="android:windowActionBar">false</item>
<item name="android:windowNoTitle">true</item>
</style>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/title"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_centerVertical="true"
android:layout_toLeftOf="@+id/buttons_holder"
android:ellipsize="end"
style="@style/TextAppearance.Sherlock.Widget.ActionBar.Title"/>
<LinearLayout
android:id="@+id/buttons_holder"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_alignParentRight="true" >
<ImageButton
android:id="@+id/acion_add"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/menu_label_add"
style="?attr/actionButtonStyle" />
<ImageButton
android:id="@+id/action_prev"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/menu_label_prev"
style="?attr/actionButtonStyle" />
<ImageButton
android:id="@+id/action_next"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/menu_label_next"
style="?attr/actionButtonStyle" />
</LinearLayout>
</RelativeLayout>