A question about DNS SRV record

[Sanapala]

Hi all,
The behavior of our DNS(BIND 8.2.2) as part of a network management app.
should be like this:
Any request coming to the DNS should be resolved to it's own IP address.
(If user is in non-authenticated VLAN and  when ever user tries to access
any thing through the browser, user is directed to a logon page which will
be displayed by a webserver running on our DNS. Once after successful
authentication, user will be  put into a valid VLAN )

We have a simple configuration for bind:
snippet from named.conf:

        zone "." {
          type master;
          file "iammaster"
        };

snippet from  iammaster file:
        *.com.  IN A  ipaddress of our dns
          *          IN A  ipaddress of our dns




This configuration worked well and the wild card (*) resolution worked for
all the domain names for the last 2 years.

Now we have to  make this DNS   (SRV) service records aware to support
Microsoft's  AD domain controller.
Required behavior should be like this:
Resolve all the queries to it's own IP except the service requests (SRV)
like _ldap._tcp.dc._msdcs.mydomain.cisco.com

I added these SRV records to the zone file, but still client can not find
the AD domain controller.
nslookup works as expected.
Your help is very much appreciated.

Thanks,
Sanapala