[3sixty]

The Easy Button tutorial is very straightforward. Unfortunately, I don’t think that posts made from the external bbPress will appear in the site Activity Stream.

There was a plugin to do that, but it’s a little out of date now, and you’d have to do some custom coding to get it to work right. The plugin author is not developing or updating it at this time.

If there’s any other way to get externally made bbPress posts to show up in the Activity Stream, I don’t know how to do it.