I was looking for the same thing, thank you Rudi!
I had the same issue as OwlyChick, I came via the tutorial video at https://outv.omniture.com?v=U1eXU2bDp683YBIKFSZhKkPdGGWiOsMo. I checked the URL carefully but still got a 502 bad gateway request.
I realized now by comparing the two urls, there's a double underscore that's easy to mistake when typing the URL directly from the video screen.