rDNS problem

[dvasunin]

Hello,
I am quite new to IPv6 in general and HE in particular and possible my question is silly. But I could not find the answer on my own.
I made an IPv6 tunnel and it worked fine. I delegated my domain to the HE nameservice, made A and 4A record for my host and it also worked fine. Now I want to play with RDNS. I edited rDNS Delegations at  www.tunnelbroker.net page and clicked on "Delegate to dns.he.net". Then I went to the dns.he.net and saw "2001:470:1f15:a21::/64 (Incomplete)" message in the top. 2001:470:1f15:a21::/64 is my tunnel and it looks correct. But I could not get rid of this "Incomplete" message. As was suggested to create new zone and be brought to the maintenance interface I clicked on the entry, but it took me to nowhere. Really, nowhere. The interface at right side had just "Hurricane Electric Free DNS Management" header and nothing to edit. I thought I'll be brought to the page where I can add host part of the ipv6 address. And when I go back I still see "2001:470:1f15:a21::/64 (Incomplete)". And, of course, reverse DNS does not work.
Can you help me, please?

Best regards,

PS. If I click on "Add a new reverse" and then provide my prefix 2001:470:1f15:a21::/64 then it exits with message "Zone addition failed. The zone 1.2.a.0.5.1.f.1.0.7.4.0.1.0.0.2.ip6.arpa already exists"