If its any help you can send sky boxes remote control codes down the RF2 input sockets as a set of frequencies. Its *MUCH* more reliable than trying to do IR into the eye. No more coming home to recordings on the wrong channel with 01 in the channel input at the start

Joeseph heenan does a usb dongle along with sourcecode for windows/linux that sends the codes out if anyones doing this with a server instead of a custom pic. Its a doddle to intergrate with mythtv by dint of triggering the compiled code as a external channel changer script. Ive always found joeseph really helpful to deal with, so he may even provide you with additional input about how it works if its not documented sufficiently on his site.
http://www.dusky-control.com/

Ive never had a lockup that my myth system couldnt recover a sky box from once I started using these units...