Unlike with vSphere 5.1 where you had an option to create user-defined storage capability, with vSphere 5.5, you will use the vCenter's tagging mechanism to create and associate tags to datastores. The tags are user defined and can have any name and category that the user would define. The tags can then be included in a storage policy to aid in the placement of VMs on them.
The following procedure will guide you through the steps required in creating user-defined tags for the datastore:
Connect to the vCenter Server using vSphere Web Client.
Use the keyboard shortcut Ctrl + Alt + 5 to bring up the storage tree in the vCenter Inventory.
Select the datastore from the Inventory to create a tag and navigate to Manage | Tags and click on the tag icon with a + on it to bring up the New Tag window.
In the New Tag window, supply a name for the tag. Make sure you supply a meaningful name matching the capability/property of the datastore...