Securing zone transfer and DDNS

[Aleksander Kurczyk]

Hello,
I just reading a book called "Pro DNS and BIND 10" written by Ron Aitchrison. I'm stuck in chapter 10 called "DNS Secure Configurations". There's described how to secure zone transfer and dynamic updates. The author has used one key to secure both the zone transfer and the dynamic updates but I want to use two separate keys. Unfortunately when I add to the keys option in server section more than one key the named doesn't start anymore. Format of the key option in the book is different than in the manual. When I remove whole server section everything works ok. Is the keys section important? For what this section is for? How can I use one key to secure zone transfer to one host and other to secure zone transfer to other host? It is possible?

Part of the named.conf:
include "key";

server 127.0.0.1 {
keys { "key"; };
};

zone "my.zone" in {
type master;
file "my.zone";
allow-transfer { key "key"; };
allow-update { key "key"; };
};

Thanks in advance.

-- 
Pozdrawiam,
Aleksander Kurczyk