NoMethodError ldap_auth_password_builder

[lindskogen]

I've defined my own ldap_auth_password_builder as per the documentation:

config.ldap_auth_password_builder = Proc.new() {|new_password| Net::LDAP::Password.generate(:ssha, new_password) }

But when I start the server there is no such method?

undefined method `ldap_auth_password_builder=' for Devise:Module (NoMethodError)