There are have been many repeater threads over the years.. I don't recall any with that specific router though -- ddwrt sure
The image your prob talking about is this one - this is a repeater bridge setup
So where in the process are you failing? Do you see the your first routers wireless using site survey? What modes are you working with G, G+N, etc. What channel are you on, what encryption are you using. As stated don't use any encryption when first setting this up! And you might have problems with wpa2??
I do believe there is some confusion on the term universal repeater and bridged repeater. dd-wrt had a universal repeater setup -- but it was more like a wisp setup. Connected to your wireless network as client, and then had its own virtual wireless network with its own ip range running its own dhcp server, etc.
A universal repeater would normally just rebroadcast the any wireless networks it sees in the area. You can buy those - range expanders, etc. So its a bit confusing when the manual for this router calls it universal repeater. Maybe it suppose to say client bridge mode?
Doesn't look like you can put dd-wrt on that router. I doubt the sky hub supports WDS or point to point bridging, etc. I would go with the universal mode.. When you do the site survey and see your router and pick it is it running security, does it ask you for the info? If not turn off security and try it.