buy a 8 pin pic adapter from Radio Shack, only 99 cents/$1.49 for the two pack. Quicksolder the WiiKey to the top of one of the adapters. (Use the Wlip guide to see where the wires are connected to their adapter, and make sure you solder to the correct top points that line up to what is in the guide.
Do you have a link to that adapter? not totally sure what you mean? do you mean a pic which you can solder wires to the other end sorta thing, basically 8 firm legs connected to wires, just kept in place with a piece of plastic?
So the top part, not the legs is what to solder the Wiikey too, so that the legs can still be inserted into the Wlip's adapter.
I asked the Wlip people and they said that that will work.