このぐらいですかね。
即興で書いたので、細かい文法とか違っているかもです。

Hello, David-san,

I heard from Mirv-san today that your IPv6 network is routed.
Conguratulations. It is very big step for innovation of PIE.

But, I cannot find your routing information on any routing registries.
e.g. on RADB:

The network for ipv6.2ch.net (it locates Datahotel, Japan), is already registered.

%whois -h whois.radb.net 2407:3000:6::/32
route6: 2407:3000::/32
descr: Livedoor Co., Ltd.
DataHotel TaskForce
origin: AS17707
notify: ipaddress@data-hotel.net
mnt-by: MAINT-AS17707
changed: ipaddress@data-hotel.net 20080623 #07:38:28Z
source: RADB

But your network seems to be not registered...

%whois -h whois.radb.net 2607:f0a0::/32
% No entries found for the selected source(s).

So, I think that you need to register the routing information on RADB, or other
routing registries, like as IPv4's one.

Regards,