How to proper delegate domain in BIND for Active Directory servers

I have to delegate domain for AD serwers. Let say example.com and I'm using Bind(dns.bind.com) on CentOS.

I added proprer configuration to named.conf and using A,NS records delegate domain to AD servers with DNS service. After that all questions should be transfered to those AD(lets call them dc1.example.com and dc2.example.com) servers even when I'm asking my DNS BIND (or am I wrong?)

Now when I execute : dig @dns.bind.com example.com A I get nothing but when execute dig @dns.bind.com example.com A I get nice answare pointing to ip of dc1.example.com (and that is correct).

Now I'm not AD administrator, I don't even have access to that AD servers. I'm admin of dns.bind.com so maybe I don't know something...

On dns.bind.com I did something like that to delegate example.com to AD servers:

named.conf:

zone "example.com" {
       type master;
       file "example.com.hosts";
       allow-update   { none; };
       allow-transfer { aclgroup1; };
       allow-query    { any; };
       also-notify    { 192.168.1.105; 192.168.1.106; 192.168.2.10; 192.168.2.11; 192.168.3.23; }; 
   };

example.com.hosts:

$TTL 1H

@ SOA @ root (
            2013120401 ; serial number
            10M ; refresh
            30M ; retry
            10D ; expiry
            1H  ; minimum
)
                ;
                NS      dc1.example.com.
                NS      dc2.example.com.




dc1             A       10.0.1.101
dc2             A       10.0.1.102

Maybe this is wrong configuration for delegating whole domain? Before I was delegating only subdomains and not for using with AD (nobody camplained then ;) so I think that was working well).