How can I determine the publishing point for streaming an HTTP stream to Adobe Media Server 5?
From the documentation, it appears that you need to use an rtmp capable encoder to send the stream to Adobe Media Server and that Adobe Media Server then shares it out as an HTTP stream based on the configuration of the publishing point.

It appears that 

rtmp://ams-ip-or-dns/livepkgr/livestream?adbe-live-event=liveEventName

is the URL to stream to for a constant bit rate, but there are other options if you are using VBR or multi-rate streams.  You can get more details under the URLs for publishing and playing live streams over HTTP section of the linked documentation.