Windows 2003 Server, No Second Disk

I just got a Dell PowerEdge 840 with no OS on it. I used dell setup disc to start loading the OS. I completed the setup and loaded Windows 2003 Server. When I go to disk management all I have is Disk 0 there is no Disk 1. I checked to make sure that I have two disk installed. I do have them and they are connected. How do I get disk 1 online so I can build my mirror?