Adding Hard Drives to Dell PowerEdge 1800

I have installed MS SBS 2003 on a Dell PowerEdge 1800. I have configured RAID 1 with two 80 GB hard drives for the operating system. I have two 250 GB hard drives installed for file storage.

On star-up the server “sees” the two 250GB drives, but I cannot access them once the system is fully loaded.

How can I configure the system for the hard drives to be available?