Early 2008 Mac Pro + ATI Radeon HD 4870 = Not working

Just took delivery of my new HD 4870 video card today. I installed it in my Early 2008 Mac Pro and booted up. I got a picture no problem on one monitor, but nothing on the other. Furthermore, the display perfpane was missing a lot of controls, like Arrangement and Detect Displays and whatnot.

I did a bunch of rebooting and swapping of cables, and determined that both the mini-display port and the standard DVI connection will drive a monitor. However, if both are plugged in, the only active display is the one plugged into the mini-display port, and there's no option to setup the secondary display.

So I booted into bootcamp, and it automatically recognized both display ports, and mirrored my desktop on both monitors. I downloaded and installed the latest windows drivers, rebooted the machine into windows once more, and was able to configure a multiple monitor display with no problem.

This tells me it's not the card and it's not the motherboard.

Booting back into mac OS, I discovered that it doesn't even recognize that the card has video ram. It thought I had no video ram in the system.

So, this all leads me to the conclusion that Apple shipped me a card that it has not yet provided driver support for.

Hey Apple, can I have my 4870 display driver now?