SOLVED.  The original megaraid sas drivers (Same as installed on the M620 Blades at Dell) had to be installed.  It is my understanding that several later megaraid sas driver versions provided on the Dell ESXi ISO's are said to meet the VMware HCL for this hardware.  However, the newer ones don't show the DataStore.
This morning I performed an Upgrade Install from ESXi 5.1.0 Update 1 to ESXi 5.1.0 Update 3 (Latest Version) on one of my VRTX's Three (3) M620 Blades.  I have the same issue that I encountered about a year ago when I tried to go from Update 1 to Update 2.  I had to downgrade to Update 1 to see the DataStore.   With Update 3, the DataStore is not showing up on that Blade.  I ran a scan to see if the DataStore would show up but it did not.  I also Rebooted the Blade which also did not help.   I must keep the Upgrade to Update 3 because of the needed CBT issue fix.   How do I troubleshoot and fix this issue of my DataStore not showing up?   Note:  I have very limited experience with Virtualization.  I just figured out today on how to access the Blades CLI's interface.   Thanks in Advance.  
Dell M620 Blade (VRTX) - ESXi 5.1.0 Update 1 Upgrade Install to ESXi 5.1.0 
Update 3 (Latest)