When comes to "external publishing point", we only accept RTMP protocol for the time being.
Meaning the external publishing point url must start with "rtmp//xxxxxx.xxxx.com/live" (example). You can exclude the "stream name" from the external publishing point url. For example, if your working rtmp stream have a url of "rtmp://mystreamingurl.com/live/stream1" , you just have to insert "rtmp://mystreamingurl.com/live/" for external publishing point url.
Once it is "restream" accross the CDN, it can be viewed in RTMP, HDS, HLS, Microsoft Smooth Streaming, RTSP protocols.
Do note that wowza only supports re-streaming h264+aac in mp4 container to HLS/HDS.
The connection flow would be: Viewer PC ->Closest Streaming Edge -> External Publishing Point