android - Overflow ActionBar actions not showing in Menu for Android 2.x

Question

I'm using ActionBarSherlock to provide a unified UI for my Android 2.x and Android 4.x users. I have a menu with 6 items.

On a 2.x, 480px wide device with an hdpi screen, only 5 of the icons show. The device has a hardware Menu button, but when I tap it, nothing shows up. I expected it to popup and show the Action that wasn't able to fit.

I expect either the three-vertical-dots button to appear in the ActionBar to show a dropdown with the overflowed actions or I expect the physical Menu button to show the old style menu with the overflowed actions.

What am I missing or what am I doing wrong?

Here is my defined menu.xml:

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >

    <item
        android:id="@+id/add"
        android:icon="@drawable/ic_menu_btn_add"
        android:showAsAction="always"
        android:title="Add"/>
    <item
        android:id="@+id/calculateNPV"
        android:icon="@drawable/menu_icon_npv"
        android:showAsAction="always"
        android:title="NPV"/>
    <item
        android:id="@+id/calculateIRR"
        android:icon="@drawable/menu_icon_irr"
        android:showAsAction="always"
        android:title="IRR/YR"/>
    <item
        android:id="@+id/send"
        android:icon="@android:drawable/ic_menu_share"
        android:showAsAction="always"
        android:title="@string/share_pdf"/>
    <item
        android:id="@+id/graph"
        android:icon="@drawable/ic_menu_gallery"
        android:showAsAction="always"
        android:title="@string/view_cashflow_diagram"/>
    <item
        android:id="@+id/deleteReorder"
        android:icon="@drawable/ic_menu_clear_playlist"
        android:showAsAction="always"
        android:title="@string/delete_reorder_cashflows"/>

</menu>