I actualy run unraid on a dell poweredge R730xd and it runs fine. The server has 2 usb ports in the back and one internal usb port (which is where I plug my unraid key). In your guide it shows on page 16 an internal system view. You can see the internal usb port on the upper left of the bottom heatsink. You just have to go to the bios and tell it to boot from the internal usb. I believe that you can even tell the integrated raid card to work in IT mode without flashing anything special.