findPreference return null in api 10

[sku4]

public class SettingsFragment extends PreferenceFragment implements OnPreferenceClickListener {
@Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        addPreferencesFromResource(R.xml.preferences);
        Preference prefAbout = (Preference) findPreference(PREFERENCE_ABOUT_KEY);

findPreference(PREFERENCE_ABOUT_KEY) return null only in api 10
in api 16+ working good

        prefAbout.setOnPreferenceClickListener(new OnPreferenceClickListener() {
            @Override
            public boolean onPreferenceClick(Preference preference) {
                AboutDialogFragment af = new AboutDialogFragment();
                af.show(getFragmentManager(), TAG_DIALOG_ABOUT);
                return true;
            }
        });
        .......
    }
        .......
}