The Hindenburg Journalist PRO, Broadcaster and Educator installer for Mac OS includes the program called "Soundflower", that you would need to route Skype and other external audio programs to Hindenburg if you are not using a commercial alternative like Audio Hijack, Loopback or Sound Siphon.

We are looking at a way of removing our reliance on SoundFlower as we agree that it is not optimal to have software with a verification signature from "Matt Ingalls" included in our installer.