Stop Windows 2008 R2 Logon and Logoff Sounds

I could not find a group policy setting in 2008 AD templates to disbale the windows logon sound.
I tried to add the reg key manually to no avail.

The only solution i could come up with was to rename the sound files.

There are in c:\windows\media\windows logon sound.wav and windows logoff sound.wav
These files are protected by trusted ownership, so you need to take ownership before renaming.