You can do that in any OS.  If you configure only the RAID 1, and create the C: partition to fill the entire VD, then in OpenManage, you will see one VD; and in Windows Disk Management, you will see one 73GB "disk".  Then, in OpenManage (or in CTRL-M), you will create and Initialize a new RAID 5 with your other disks.  Once complete, you will see a new "disk" in Windows Management filled with Unpartitioned Space.  You will format and partition that disk as desired (you may to reboot before you can use it, and you may need to "initialize" the disk in DM too).
New larger drives in a Dell 2850 with a PERC 4e/Di controller. Where do I begin? I'm hoping someone could shed light on an my plan to increase the disk space seen in each partition. Originally the server had 36 GB drives in it but one drive failed about a year ago so we replaced it with a larger drive (76GB?). Well another drive failed so we replaced all of the rest of the drives with larger 146GB ones. The issue is I cannot see the rest of the unused space by the OS. Drive 0  - 76GB      virtual disk 0       RAID 1Drive 1  - 146GB     virtual disk 0       RAID 1 Drive 2  - 146GB     virtual disk 1       RAID 5Drive 3  - 146GB     virtual disk 1       RAID 5Drive 4  - 146GB     virtual disk 1       RAID 5 There are three partitions, the first one obviously has the OS and other software ( I didn't set it up this way). The other software is Wordpress, Perl, a third party FTP server and other stuff. My boss who could do this in his sleep said all I should do back up everything to an external hard drive ( I'll also back it up to tape). Then reinstall the OS but when prompted, create the larger RAID arrays, then create the same partitions with larger disk space and then restore from the back ups. Does this sound accurate? Or am I missing something completely?
Dell 2850 PERC 4e/Di larger drives installed and cannot use unallocated space