[keycloak-user] User attributes

With keycloak 1.8.0 RC1, I'm using user federation (Active directory) for users: the active directory is in Read Only mode. I can assign roles to user. I can retrieve user federation attributes I need. I can assign roles and attributes at group level. To some user, I would like to add attributes not in the Active Directory. But it fails : 'Error! User is Read Only!'. Is there a way to specify user attributes in such case : 'user federation is read only' ? Thanks Gerard