Reverse DNS on routed /48 for dummies

[lannetplv6]

Hi,
I have obtained 2001:456:1234::/48 space and I'd like to configure rev DNS on couple of IPs. Free DNS tool is a bit clunky, so my questions are:
Do I need to move my domain there, or I can just create IN A record on my current DNS server pointing to the IP(v6)?
If not, how can I configure it? When I am clicking on add new reverse and then paste my 2001:456:1234::/48 prefix it says it is already added. But I can't find it anywhere. How it works?

[cholzhauer]

First, you should use the ipv6 documentation prefix if you're not going to post your real address

Second, to answer your question, you can definitely host the reverse DNS range, you just need to put the server that does that under your tunnel config on the he site

[lannetplv6]

OK, I have delegated both /64 and /48 prefixes to he.net nameservers, but can activate only /64. If I click on /48 to activate then I am getting blank page. Also I have created first PTR record to one of /64 IPs (not server or client IPs) and ran query against he.net nameserver but there is stil no revdns set on that IP.

[cholzhauer]

I have not used the HE service for DNS, so I can't help you with  specifics on that.  But, you have the /48 so there's no reason to do anything with the /64