Android : Creating a Preference Screen with support (v21) Toolbar

I was having trouble using the new Material Design toolbar in the support library on a Preference screen.

I have a settings.xml file as below:

<PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android">
    <PreferenceCategory
        android:title="@string/AddingItems"
        android:key="pref_key_storage_settings">

        <ListPreference
            android:key="pref_key_new_items"
            android:title="@string/LocationOfNewItems"
            android:summary="@string/LocationOfNewItemsSummary"
            android:entries="@array/new_items_entry"
            android:entryValues="@array/new_item_entry_value"
            android:defaultValue="1"/>

    </PreferenceCategory>
</PreferenceScreen>

The strings are defined elsewhere.