I haven't seen this confirmed anywhere, so I figured I'd be the first one to do it here incase anyone else is searching for a relevant answer.
If you follow this guide to the letter:
http://tweaks.com/windows/52279/how-to-create-a-windows-to-go-usb-drive/
Windows 8 is capable of booting natively, from EFI, on the Mac Pro. This means that the EFI partition shows up as "EFI Boot" under the OS chooser (holding the ALT key when you reboot), and you can select it and boot Windows 8 from an external device.
Everything works OOTB on the 2010/2012 Mac Pro. Bluetooth needs drivers (which you can extract from Apple's bootcamp drivers, or just leave it alone- the Mac Pro Bluetooth card emulates a USB HID keyboard and mouse with the devices you used to select the OS from the chooser screen if you don't install the BT chipset drivers), and the AMD Catalyst drivers should be installed for best performance- but other then that it absolutely flies, even off a USB disk drive.
This is NOT bootcamp. Bootcamp runs through a CSM module under EFI that allows one to boot MBR-based operating systems from a legacy partition. Windows 8 x64 natively supports EFI booting from a USB flash key or USB disk drive on damned near every recent Macintosh I've tried (2012 iMac, 2012 Macbook Pro, 2010 Mac Pro) flawlessly, which has nothing to do with Bootcamp at all.
So if you're stuck with a RAID card that only really works in OS X and you don't want to mess with that, then this is a totally viable alternative to run Windows on your Mac Pro.
-SC
If you follow this guide to the letter:
http://tweaks.com/windows/52279/how-to-create-a-windows-to-go-usb-drive/
Windows 8 is capable of booting natively, from EFI, on the Mac Pro. This means that the EFI partition shows up as "EFI Boot" under the OS chooser (holding the ALT key when you reboot), and you can select it and boot Windows 8 from an external device.
Everything works OOTB on the 2010/2012 Mac Pro. Bluetooth needs drivers (which you can extract from Apple's bootcamp drivers, or just leave it alone- the Mac Pro Bluetooth card emulates a USB HID keyboard and mouse with the devices you used to select the OS from the chooser screen if you don't install the BT chipset drivers), and the AMD Catalyst drivers should be installed for best performance- but other then that it absolutely flies, even off a USB disk drive.
This is NOT bootcamp. Bootcamp runs through a CSM module under EFI that allows one to boot MBR-based operating systems from a legacy partition. Windows 8 x64 natively supports EFI booting from a USB flash key or USB disk drive on damned near every recent Macintosh I've tried (2012 iMac, 2012 Macbook Pro, 2010 Mac Pro) flawlessly, which has nothing to do with Bootcamp at all.
So if you're stuck with a RAID card that only really works in OS X and you don't want to mess with that, then this is a totally viable alternative to run Windows on your Mac Pro.
-SC