Datastore Naming Rules

I'm trying to get a definitive answer on what the rules are for naming Datastores?  I can't seem to find any information on what is allow and what is not allowed as names for datastores.

So far, I found this document

http://kb.vmware.com/selfservice/microsites/search.do?language=en_US&cmd=displayKC&externalId=2012890

Which says [ ] / are not allowable characters, with a max of 42 characters

Then I found this document

http://www.vmware.com/support/developer/vc-sdk/visdk400pubs/ReferenceGuide/vim.Datastore.html

Which says \ and % aren't allowable (although I can create a datastore with % just fine..)

As for Maximum length, I've seen stuff around the forums saying 128, 42, 31, and 255 character lengths.

Is there any document that maps out the datastore naming rules?  Specifically for vSphere 5.1 (VMFS-5 and VMFS-3).  Also, are the naming rules different for NFS shares?