I've recently completed this install on my 2012 ST and it was made so easy thanks to this guide.
Took me about 6 hours in total;
Hour and a half to get the ***** airbag off.
Half hour to fit, enable and test the switch.
4 hours to cut the steering wheel!!!!
Just as an aside, something that isn't mentioned in this guide is that if you already have the audio controls on the bottom right of the wheel you'll need a totally different wiring loom that I was only able to pick up from Ford. I've attached a picture of the label on the box for your benefit.
Happy camping everyone!