Upgrade Path from Mediasmart Home Server to Something Stronger?

Within the Disk Management tool of Server Manager I'm showing the entire RAID volume as Disk 0 (the name Volume_0001 doesn't show up anywhere). But when I right click it, there's no option to partition it, only to create a New Simple Volume.

I think that's what you need to do. Make a New Simple Volume, and then build a logical drive in that volume.

It's not like you have any data on it to lose, so experiment!