Any way to add a Notification Sound?

[Toten]

Hi. I am trying to make "NOTIFICATION_FRIENDSHIP_EXPIRED" emit a notification sound by editing game core files. I added the following script in each file:

NotificationSound.xml,

    <NotificationSound>
      <ID>NOTIFICATION_FRIENDSHIP_EXPIRED</ID>
      <AudioScript>AS2D_EVENT_NOTIFICATION_FRIENDSHIP_EXPIRED</AudioScript>
    </NotificationSound>

Audio2Dscripts.xml,

    <Script2DSound>
      <ScriptID>AS2D_EVENT_NOTIFICATION_FRIENDSHIP_EXPIRED</ScriptID>
      <SoundID>SND_EVENT_NOTIFICATION_FRIENDSHIP_EXPIRED</SoundID>
      <SoundType>GAME_SFX</SoundType>
      <iMaxVolume>45</iMaxVolume>
      <iMinVolume>45</iMinVolume>
      <bDontTriggerDuplicates>True</bDontTriggerDuplicates>
      <iDontPlayMoreThan>1</iDontPlayMoreThan>
    </Script2DSound>

and AudioDefines.xml.

    <SoundData>
      <SoundID>SND_EVENT_NOTIFICATION_FRIENDSHIP_EXPIRED</SoundID>
      <Filename>NotificationFriendshipExpired</Filename>
      <LoadType>DYNAMIC_RES</LoadType>
      <bDontCache/>
      <bOnlyLoadOneVariationEachTime/>
    </SoundData>

Finally I put NotificationFriendshipExpired.wav in ~\Sid Meier's Civilization V\Resource\Common (because SoundData.fpk exists there) , it does not work.
I have no idea now. What do I have to do next ? Thank you in advance.