from what I can see, and unless I skipped over something in the reading.... that part is useless.
The cheaper way to do this is by 2 methods...
the "professional" way....
Get a cig lighter plug adapter from radio shack. Its basically the thing a cig lighter plugs into. It should have 2 wires coming from the back. 1 wire is positive, 1 wire is negative. Those hook to a +/- wire in your car. Plug your satellite radio power adapter into it, and you've got the exact same thing as what they are showing.
the even cheaper way...
First off you'll need speaker wire, or atleast 2 separate wires...Now strip back both wires about an inch. Take one and stick it through the ground side on your adapter...Now take electrical tape and wrap it around so that the wire doesn't come loose. Now with the other wire, push in on the tab on the top and sort of cram the wire down into the adapter. It doesn't have to go in much, just enough so that it touches really. Now tape it as well. And now once again you have the same thing...for much less than $25.