Different sized hard drives in Dell 2950

Hi Folks, just a very basic question -  is it possible to have (2 x 100GB HD - in RAID 1) and (1 x 1TB HD - Standalone) in 2950?

When I installed Vmware ESXi 5.1 on RAID 1 partition; the 1TB disk was not present. I have just now added 1TB disk for extra storage but its not visible to ESXi. Do you have any idea why this could be happening?

Thanks!