It's really not useful replying to an old thread, particularly when your problem isn't related, as is this case.
A single LUN can compromise of only one datastore.
You have created datastore1, at 1.9TB, on one large LUN. You cannot then add a datastore2 to the remaining space.
If you require a series of smaller datastores, you should use HP's ACU to create them at this size, so VMware will see them as separate disks.