It is this post I am talking about:
https://www.wowza.com/forums/showpost.php?p=33210&postcount=15
This will work with RTSP and RTMP. You need to turn on RTMP authentication as described in this package:
http://community.wowza.com/t/-/45
Then if you implement a class as described here and set the property in the application properties then it will call your class to do the authentication.
Charlie