Internal domain name same as external domain name

I set up a Windows 2003 AD DNS Server which is also running exchange 2003. The IP address is 192.168.0.232. I gave the name of the internal Domain badmc.org. I am using DSL with no public IP.The company has an isp who stores their mail with the same name badmc.org. The external mail server is mail.badmc.org at Public IP 66.176.232.98. I want users on the inside to send mail via the exchange server using outlook and recieve mail via POP3 (mail.badmc.org)from the ISP in outlook as well. I have my smtp connector setup in exchange so sending email out is fine. When I want to receive mail via my POP3 account from mail.badmc.org (66.176.232.98) I am getting an error saying that the server was found but did not respond. I know this is a DNS problem. I already have fowarders setup on my Internal DNS server to point to my internet service provider. My internal dns clients are pointing to my internal dns server (can access the internet). On my dns server I added an A record called mail assigned to 66.176.232.98. I need to know what I'm doing wrong