DDNS : Multiple domains

[Nicolas Ecarnot]

Hello,

Our DDNS setup is 100% OK since years.

Our global config is using :

------------------------------------
ddns-update-style interim;
ddns-domainname "olddomain.net.";
ddns-rev-domainname "in-addr.arpa.";

zone olddomain.net. {
   primary 192.168.10.1;
   key olddomain-nsupdate;
}
------------------------------------

For a specific host, I'm trying to ask the DHCP server to register the 
DNS record with a second domain.

Before :

------------------------------------
host myhost {
   hardware ethernet aa:bb:cc:dd:ee:ff;
   fixed-address 192.168.1.2;
}
------------------------------------

After :

------------------------------------
host myhost {
   hardware ethernet aa:bb:cc:dd:ee:ff;
   fixed-address 192.168.1.2;
   option domain-name "newdomain.net";
}

# I added :
zone newdomain.net. {
   primary 192.168.10.2;
   key newdomain-nsupdate;
}
------------------------------------

I'm witnessing that the correct new domain is sent to the host.
But I see that the server is building myhost.olddomain.net and sending 
it to the old DHCP server.

My questions :
- what is the way to tell the DHCP server to use the new domain for this 
host?
- how comes the newdomain.net zone settings are never used?

Thank you for your help.

-- 
Nicolas ECARNOT