[Samba] Ubuntu client ddns failure

[steve]

We're wrong here:
  dig lubuntu-laptop

; <<>> DiG 9.9.4-rpz2.13269.14-P2 <<>> lubuntu-laptop
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NXDOMAIN, id: 414
;; flags: qr rd ra; QUERY: 1, ANSWER: 0, AUTHORITY: 1, ADDITIONAL: 1

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;lubuntu-laptop.                        IN      A

;; AUTHORITY SECTION:
.                       6906    IN      SOA     a.root-servers.net. 
nstld.verisign-grs.com. 2014052000 1800 900 604800 86400

;; Query time: 1 msec
;; SERVER: 192.168.1.16#53(192.168.1.16)
;; WHEN: Tue May 20 17:19:04 CEST 2014
;; MSG SIZE  rcvd: 118

With the fqdn, we're OK:
dig lubuntu-laptop.hh3.site

; <<>> DiG 9.9.4-rpz2.13269.14-P2 <<>> lubuntu-laptop.hh3.site
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 61509
;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 1, ADDITIONAL: 2

;; OPT PSEUDOSECTION:
; EDNS: version: 0, flags:; udp: 4096
;; QUESTION SECTION:
;lubuntu-laptop.hh3.site.       IN      A

;; ANSWER SECTION:
lubuntu-laptop.hh3.site. 3600   IN      A       192.168.1.22

;; AUTHORITY SECTION:
hh3.site.               900     IN      NS      hh16.hh3.site.

;; ADDITIONAL SECTION:
hh16.hh3.site.          900     IN      A       192.168.1.16

;; Query time: 2 msec
;; SERVER: 192.168.1.16#53(192.168.1.16)
;; WHEN: Tue May 20 17:18:32 CEST 2014
;; MSG SIZE  rcvd: 103


It can find the fqdn but not the short hostname. How can I fix that?
Cheers