Configuring DHCPv6 Pool

This follows on from IPv6 Stateless config. The configuration below shows how you can allocate and address using DHCPv6. However the only issue i've been trying to solve is that the R1 interface ends up allocating a /128 subnet (ie host route). It should really be a /63 subnet as configured.

R1 Config
ipv6 unicast-routing
!
interface Ethernet0/0
 no ip address
 ipv6 address dhcp
 ipv6 enable
!

R2 Config

ipv6 unicast-routing
ipv6 dhcp pool myp
 address prefix 2001:2002::2/63
 dns-server 2001:1::1
 domain-name ipv6test.net
!
interface Ethernet0/0
 no ip address
 ipv6 address 2001:2002::1/63
 ipv6 enable
 ipv6 dhcp server myp
!

R1#show ipv6 dhcp interface
Ethernet0/0 is in client mode
  Prefix State is IDLE
  Address State is OPEN
  Renew for address will be sent in 09:34:42
  List of known servers:
    Reachable via address: FE80::A8BB:CCFF:FE00:6600
    DUID: 00030001AABBCC006600
    Preference: 0
    Configuration parameters:
      IA NA: IA ID 0x00030001, T1 43200, T2 69120
        Address: 2001:2002::FDD6:182B:4D68:2465/128
                preferred lifetime 86400, valid lifetime 172800
                expires at Mar 22 2012 07:01 AM (164082 seconds)
      DNS server: 2001:1::1
      Domain name: ipv6test.net
      Information refresh time: 0
  Prefix Rapid-Commit: disabled
  Address Rapid-Commit: disabled