IdStory Identity Manager

USECASE:
I need to use LDAP just for authentication into IdM. I have HR system as a source of identities and target system. We need to synchronize all users from HR a let them login into IdM, but we want to avoid some passwords transmissions.
So I want to use local LDAP (which I don't want to manage from IdM) for authentication into IdM.

Now it's not easily possible. When I connect this LDAP into IdM I need to do mapping with a password. Since I can choose just between synchronization/provisioning mapping, and for authentication, I need to choose provisioning. But then I am managing password on this LDAP and see this LDAP in password change GUI, which is wrong.

We need some general feature for an only-authentication system.

If we want to have this admin-friendly, I would probably expect a new type of mapping - Authentication.
Alternatively, authentication system and login attribute can be set just by properties.