Adding cruise control to a 2011 Prius from Japan

I recently bought a 2011 Japanese import Prius without cruise control and followed the instructions in http://priuschat.com/attachments/toyota-prius-2010-cruise-control-pdf.27367/ but it doesn't work, the cruise light doesn't come on when the ON/OFF button is pressed and if I assume it's just the light that doesn't work and try pressing the ON/OFF button once and then SET, it does nothing (as I did in my previous Prius that had cruise control). The switch I got from eBay and someone in China sent it to me, however I was wondering if there are any connections between the steering wheel connector and the computer that might perhaps be missing.

So, can anyone provide some information on where the two wires from the cruise switch actually go to? I mean the particular pins on a particular connector on a particular unit (which is under the bonnet I hope). If I have this information then I could check with a multi-meter at the connector if the switch is doing anything and if not, trace the problem back from there.

I do find driving the Prius at a constant speed around the speed limit without cruise control quite difficult because there are no audible cues from the motor if you're speeding up or slowing down...

 

Thanks for the tip. However I only found the Owners Manual and nothing showing wiring diagrams or the like.