DNS and dynamic IP: help needed

hi all,

I'm using a dynamic DNS to reach my site from internet: mysite.mine.nu
(dyndns.org).
I want to setup on the lan a DNS server (linux debian) for all the
computers of the LAN. The name of the computers will be
computerX.mysite.mine.nu.
I user forwarders in named.conf

Here is my zone file mysite.mine.nu:

@ IN SOA dnserver.mysite.mine.nu. root.mysite.mine.nu. (
199802151 ; serial, todays date + todays
serial #
8H ; refresh, seconds
2H ; retry, seconds
1W ; expire, seconds
1D ) ; minimum, seconds

NS dnsserver
MX 10 mailer.mysite.mine.nu.

localhost A 127.0.0.1
dnsserver A 10.0.0.1
computer1 A 10.0.0.10
computer2 A 10.0.0.20
mailer A 10.0.0.30
mailer.mysite.mine.nu. A 10.0.0.30

mysite.mine.nu. A 10.0.0.10

computer5 A 192.168.0.10
computer6 A 192.168.0.20


The problem is:
# nslookup mysite.mine.nu
I get the answer:
Name : nu.mine.nu
Address: 203.164.2.199
Aliases: mysite.mine.nu.mine.nu

I want to get the answer: mysite.mine.nu 10.0.0.10 and not the answer of
my dynamic DNS (dyndns.org).

I read again the docs and surf the web, however I'm still missing something.

Any help would be appreciated.
Many thanx in advance.
Mike.