Subbed it out. I wired all of the shop and house circuits as well as the mains for them, but this was a totally different animal. I am not sure if you can even do it yourself, as you need to call Generac for a startup code and I thought I remembered the installer saying that they will only give it to professionals who are setup with Generac to do it. I could be wrong on that, but if you are planning to do it yourself, I would check first.
-John