How to set up IPv6 in OpenVPN on Windows Server 2008 R2?

Question

openvpn

There is a server: Windows Server 2008 R2 - it has OpenVPN installed, it is configured and works fine over IPv4, but does not want to work over IPv6. It works on the IPv6 server.
It is necessary to transfer IPv6 from the server to the client machine, while the IP is assigned to the client machine, for example: 2a00:xxxx:xxxx:xxxxx::80:1000/112
The server is pinged from the client machine: 1 - ALL OK
Also, the external IPv6 server is pinged from the client machine: 2a00:xxxx:xxxx:xxxxx::1:1 - OK
But there is no connection to the Internet via IPv6 on the client machine:
ping -6 google.ru
Packet exchange with google.ru [2a00:1450:4001:800::2003] with 32 bytes of data:
Request timed out.
Timed out request.
Timed out request.
Timed out request.
Ping stats for 2a00:1450:4001:800::2003: Packets : sent
= 4, received = 0, lost = 4 : 2a00:xxxx:xxxx:xxxxx::1 DNS: 2620:119:35::35, 2620:119:53::53 Server.ovpn file: dev tun dev-node "VPN Server" proto tcp6 proto udp6 port 443 ca ca.crt cert server.crt key server.key dh dh2048.pem topology subnet server 10.8.0.0 255.255.255.0 server-ipv6 2a00:xxxx:xxxx:xxxxx::80:0/112 push "route-ipv6 2000:: /3"
push "tun-ipv6"
cipher AES-128-CBC
comp-lzo
mssfix 1420
keepalive 10 120
max-clients 32
client-to-client
persist-key
persist-tun
verb 3
mute 20
push "redirect-gateway def1"
push "redirect- gateway ipv6"
push "dhcp-option DNS 208.67.222.222"
push "dhcp-option DNS 208.67.220.220"
sndbuf 542544
rcvbuf 542544
push "sndbuf 542544"
push "rcvbuf 542544
" the correct routing on the server is configured.
In which direction should I dig?

Answer 1

/etc/sysctl.conf
net.ipv6.conf.all.forwarding=1
net.ipv6.conf.all.proxy_ndp = 1
Then execute:
sysctl -p

Answer 2

OpenVPN runs on Windows Server unfortunately the instructions for Linux won't help.