Microsoft Knowledge Base Article 884116 contains the following Introduction:

This article describes how to create and apply a custom application directory partition on an Active Directory directory service integrated Domain Name System (DNS) zone.

You can create a custom Active Directory partition by using the DnsCmd command. The steps in this article create an example custom application directory partition that is named CustomDNSPartition. This application directory partition is located in the example domain These steps configure the example application directory partition to be hosted on the following two example domain controllers:                      
Note DnsCmd.exe is included in the Microsoft Windows Server 2003 Support Tools. To install the Windows Server 2003 Support Tools, double-click Suptools.msi in the Support\Tools folder on the Microsoft Windows Server 2003 CD.