|I don't think it is going to work...|
"Typically, a Windows Server 2003 DNS namespace is deployed to mirror an Active Directory forest and domain infrastructure. In such a deployment, a partition of the DNS namespace is set aside for Active Directory, where a DNS domain name such as corp.contoso.com is used support the Active Directory forest root domain, and then subdomains of this name are created to suit additional Active Directory domains as needed."
If it does not then you may have to tunnel through your firewall with SSL or VPN but that would suck and you would probably see a performance hit.
This is why you never use special characters in your Domain Name or use well known DNS suffixes like .COM and for the love of Pete Microsoft will you change that darn example you have in your DCPROMO wizard?