Hi jblanc03 I'm just posting this here in the event that somone else stumbles upon this thread.
See the other thread here -- http://forum.commvault.com/forums/thread/44386.aspx
You will need to map/present the ESXi datastores to the server that is running the Virtual Server Agent (VSA) just as you would to an ESXi host, however first you need to make sure to disable automount in Windows so that windows does not try to initialize the disk. Failure to do this could result in data loss on your ESXi datastores (diskpart | automount disable).
Please see this article for more information- http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2002227
When you present the datastores to the server running the VSA you have a couple of options - do you want to do backups with SAN transport or would you like to be able to do backups & restores via SAN transport? If you'd like to be able to do restores you will need to make sure you present the datastore as read/write and you'll need to clear the read only flag in Windows once you've presented the datastore (see this article for more information: http://blogs.technet.com/b/askcore/archive/2011/06/02/my-disk-is-read-only-help.aspx).
If you need to use masking is going to depend on how your environment is setup but as long as the VSA client can read/write to the ESXi datastores you shouldn't have any problems doing SAN transport backups/restores.
Your datastores should show up in Disk management like this (do NOT bring them online):
Hopefully that helps to clarify your questions. Please let me know if you have additional questions.