We have a client using DS Auth for Forms and Identity Providers to synchronize user assignment with through domain controller.

Since the Identity Providers tab does not include any features for managing Forms access in the license assignment we just added the same AD group to the DS Group "Forms Users" as a Member.

In DS Auth you must create a Group that determines how their Forms Account will be created in Forms.

However when adding someone to the group, it does create and license a DS User, but no Forms user. I am still manually going in and adding them to the Forms Users group by their account.