John,
Second things first, (easiest)!
You need to RDP into the server first. Then, on the Start Menu, highlight My Computer, 'right-click' and select 'Manage'.
From the Computer Management box that pops up, select Disk Management which should now show all the drives in the Server. Highlight your new non-pooled drive and again 'right-click'; from this, you can give this drive a Drive Letter, (well outside the ones used by WHS). This new drive letter can now be mapped as a Network Drive from any of your Clients.
Not seeing your server, it does have an IP/subnet mask within the same group as your Clients? You don't have any firewall blocking?
HTH,
Colin