Hierarchical Mobile IPv6 (HMIPv6) is a protocol that enhances Mobile IPv6 (MIPv6) with faster handovers. Neither HMIPv6 nor MIPv6 provides ways to authenticate roaming mobile nodes, although visited networks will need to check if mobile nodes can be authorized access. A solution is required before MIPv6 can be commonly deployed. Mechanisms to integrate Mobile IPv4 and the Diameter protocol for authentication, authorization and accounting (AAA) have proved to be a useful solution for IPv4. However, a similar mechanism does not yet exist for IPv6. We therefore propose a modification to HMIPv6 to allow for authenticated access for IPv6 supported mobility. HMIPv6, as well as Diameter protocols, supports transportation of AAA information and extends MIPv6 with mobility anchor points. Our proposed solution shows how different mechanisms for secure roaming can be united in an efficient, secure and scalable manner. Furthermore, since HMIPv6 is a protocol designed to reduce the delay and signaling overhead of MIPv6, our proposal represents a way to integrate fast handovers with authenticated and authorized access.