Issue setting up reverse DNS with BIND9

[Kolusion]

I setup a DNS server last month but didn't setup a reverse DNS server. Now I need to do it and having trouble getting things up and running, and hoping my Linux bros can help me out:
I'll keep it real simple for you guys, so here it is:

named.conf.local:

zone "78.456.123.in-addr.arpa" {
type master;
notify no;
file "/etc/bind/db.78";
};

db.78:

;
; BIND reverse data file for local loopback interface
;
$TTL 604800
@ IN SOA ns1.mydomain.com. me.mydomain.com. (
1 ; Serial
604800 ; Refresh
86400 ; Retry
2419200 ; Expire
604800 ) ; Negative Cache TTL
;
@ IN NS ns1.
1.0.0 IN PTR ns1.mydomain.com.

Where have I stuffed up (to be fair on myself, I was guided off an Ubuntu manual written for BIND8 (thats the best they've got))?

[Kolusion]

Hey its all cool guys. Turns out I have to tell my ISP I am running a DNS server.

I've decided to **** running a reverse DNS server anyway. I was only going to do it because some mail servers accuse me of being spam because I imagine they tried to do a reverse DNS on my IP. ****in noob cunts, should try a normal DNS so **** them. Dumb cunts!

Thanks.