Android user preference fragment not displaying
===

I am trying to establish a settings screen for my Android 4.0+ app. I can not get the two checkboxes `vibratePreference` and `soundPreference` to display. I don't think `UserPreferencesFragment` ever instantiates.  Below are the files involved. I've been on this for a couple of nights and I can not figure out what I'm missing. What am I over looking? 

Thanks, PLA

preferences_headers.xml

    <preference-headers xmlns:android="http://schemas.android.com/apk/res/android" >

        <header
            android:fragment="com.hometelco.hfa.activities.UserPreferencesFragment"
            android:summary="Home Field Advantage user settings"
            android:title="User Settings" />

    </preference-headers> 

preferences.xml 

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

        <PreferenceCategory android:title="User Settings" >
            <CheckBoxPreference
                android:defaultValue="true"
                android:key="vibratePreference"
                android:summary="Vibrate on adds and updates"
                android:title="Vibrate" />
            <CheckBoxPreference
                android:defaultValue="true"
                android:key="soundPreference"
                android:summary="Play sound on adds and updates"
                android:title="Sound" />
        </PreferenceCategory>

    </PreferenceScreen>

UserPreferencesActivity.java


    package com.hometelco.hfa.activities;

    import java.util.List;

    import android.preference.PreferenceActivity;
    import android.util.Log;

    import com.hometelco.hfa.R;

    public class UserPreferencesActivity extends PreferenceActivity {
    	private static final String TAG = "UserPreferencesActivity";

    	public void onBuildHeaders(List<Header> target) {
    		Log.i(TAG, "onBuildHeaders before load");
    		loadHeadersFromResource(R.xml.preference_headers, target);
    		Log.i(TAG, "onBuildHeaders after load");
    	}
    }

UserPreferencesFragment.java

    package com.hometelco.hfa.activities;

    import android.os.Bundle;
    import android.preference.PreferenceFragment;
    import android.util.Log;

    import com.hometelco.hfa.R;

    public class UserPreferencesFragment extends PreferenceFragment {
    	private final static String TAG = "UserPreferencesFragment";

    	public void onCreate(Bundle savedInstanceState) {
    		Log.i(TAG, "UserPreferencesFragment onCreate");
    		super.onCreate(savedInstanceState);
    		addPreferencesFromResource(R.xml.preferences);
    	}
    }

