Retrieving a login reference for iControlREST remote auth

I've set up LDAP integration on my Big-IP VE, v12.1. I get a token back when I pass in my AD username and creds, but the results are suspect, specifically:

loginReference    : @{link=https://localhost/mgmt/cm/system/authn/providers/local/login}
loginProviderName : local

The articles and docs about token-based auth mention the Login Reference and say it is provided by the sys admin. Well, I'm the sys admin here and I don't see what I can set or generate the Login Reference value, and the one returned by the POST to the AUTH url (above) doesn't seem right.

It's like it doesn't recognize that remote auth is set up. In the admin UI, authentication is set to Advanced: Remote LDAP. What am I missing?

Thanks, Joel