going to try this with a time capsule instead (seeing as I already have one in a different location)
surely this must be possible??!!
internet -------> router -------> wifi -------> time capsule -------> ethernet -------> sky hd box
-------> apple tv2 etc
very much doubt it
Just because it's got an Ethernet port, doesn't mean it supports internet connection sharing.
In order for the device to share the connection it needs to be able to act as a gateway, passing through the traffic from one device to another, basically you need a device that can act as a router or gateway, meaning you need either a second wireless router or access point or a PC / apple that supports sharing or a long length of cat5e, I'm guessing you're trying to do it on the cheap but you're gonna need to put your hand in your pocket.