You must configure AND initialize the virtual disk (array) ... check the Advanced and Initialize boxes during creation of the VD. You may also be using a version of "server assistant" (obsolete) that doesn't support the hardware in your server.
hello all and good day  I have a PowerEdge 2900 that has been wiped and raid configured with 2 drives and ready for os install. however when trying to use the server assistant I get an error that stats can not detect drives or they are not initialized . I have don't all the raid configuring and should be ready. I took a look in the main server bios and I don't see the raid controller listed in the boot sequence. all I see is cd rom on sata b and hard disk. before the server was wiped the raid controller was listed in the boot sequence menu. did I change a setting I shouldn't have or am I missing part of the process? anyone lend a had and solving this issue? I would like to get the server back up and running. the server has a perc 6i when I got the server is was up and running. however it came from a health care facility and needed to be wiped. I wiped it myself just by going in the raid controller and deleting the VD and reconfiguring it with a new configuration.   please tell me I didn't just make the heaviest paper weight in my office.  
PowerEdge 2900 server raid