Currently, we must store OAUTH Authorization Grants in an existing LDAP attribute.
The attribute must either be something that already exists (and is not specific to NAM), or the schema must be extended.
Not everyone is able or is willing to extend their schemas. Also, it may be risky to use an existing attribute that may be, in the future, used by some other program.

The request is to allow OAUTH Authorization Grant data to be stores on an external database.
As an alternative, it could also be stores on the local LDAP server, even if the user store is using an external LDAP server (ex.: Active Directory).