Victim is an ESXi 5.1 running on a HP DL380 G5 with a Smart Array P400 RAID card. I migrated the 6 drive RAID 5 to 7 drive RAID 5. Logging into Virtual Center (vCenter Appliance v5.5) using the Vmware Vsphere Client. The configuation showed that the new space was now available. Normally one clicks on the "Increase" button, and add an extent.
For whatever reason, despite seeing the extra space, I was not able to add the extent.