Cisco WAN :: IPv6 ISG On ASR1000

We use ISG on asr1000 (l3 routed subscriber). Now we are trying to implement ipv6 isg sessions. so.. for ipv4 sessions we have

radius-server attribute 8 include-in-access-req
radius-server attribute 32 include-in-access-req but for ipv6 there is no such attribute#radius-server attribute ?
  11           Filter-Id attribute configuration
  188          Num-In-Multilink attribute configuration
  218          Address-Pool attribute
  25           Class attribute
  30           DNIS attribute
  31           Calling Station ID
  32           NAS-Identifier attribute
  4            NAS IP address attribute
  44           Acct-Session-Id attribute
  55           Event-Timestamp attribute
  6            Service-Type attribute
  60           CHAP-Challenge attribute
  61           NAS-Port-Type attribute configuration
  66           Tunnel-Client-Endpoint attribute
  67           Tunnel-Server-Endpoint attribute
  69           Tunnel-Password attribute
  77           Connect-Info attribute
  8            Framed IP address attribute
  95           NAS IPv6 address attribute
  list         List of Attribute Types
  nas-port     NAS-Port attribute configuration
  nas-port-id  Nas-Port-Id attribute configuration
what is best practice for authorize ipv6 l3 subscribers ?