bootcamp no device drivers Windows 8.1 64 Bit

Hello,

I'm trying to install Windows 8.1 Pro 64 Bit on my Mac Pro (Late 2013)

So far, I have tried the following:

• USB 3.0 Drive created with the Boot Camp Assistant
• USB 2.0 Drive created with the Boot Camp Assistant
• USB 3.0 Drive created with the Windows USB Creation Tool + Manually adding Boot Camp Support Software
• USB 2.0 Drive created with the Windows USB Creation Tool + Manually adding Boot Camp Support Software

The issue I am having is that I am unable to continue past the first screen in Windows Setup, I get an error message stating that no device driver software has been found, and to locate the software. I've tried selecting all possible drives in the browse menu, and there is no software found.

I'm not sure if I'm missing something, or if the Boot Camp Assistant software is just broken or something. But any help with this matter would be greatly appreciated.