Has anybody figured how to use the xA steering wheel controls with a Pioneer AVIC-Z1?

I understand that it can be done using the infrared port, but what about using the wired remote cable available on the Z1?

It feels kinda stupid to have the steering wheel controls and not being able to use them. I wouldn't mind removing them, but as far as I can tell Scion/Toyota doesn't sell a replacement cover plate.

Thanks,

E.