Since a "Genie" HR34, HR44 or HR54 are SWM only I'd would think he had to put a SWM-8 and 29v PI inline to provide SWM signals rather than the raw signals from the dome. His description indicates he used just a "green label" splitter and SWM dish PI (21v) normally used with a SWM LNB on a Slimline. I would think to do that, he would have had to swap out the LNB.
I'd too would love to see how he pulled it off.
Here are Winegard's instructions on how to hook up legacy dishes and Slimlines to DirecTV's SWM only receivers.
http://www.winegard.com/kbase/upload/2452242.pdf