how do i install my ati x 1900 video card on my mac pro correctly. i install it, turn on and I get this message: "The power cable for your graphics card is not properly connected" To connect the cable, turn off your computer. Then plug one end of the power cable into the connector on the logic board and the other end into the card." now i have NO idea where to plus in the power to the Logic board. I have the included 6 PIN PCIe aux. power cable. any help would be HUGELY appreciated. a image or diagram would be awesome. thanks guys.