Dual 10/100 Ethernet Configuration

I have a production server behind a PIX Firewall and need to use Secure FTP. The AIX box has two network adapters, one (en0) for internal network and the second (en1) will be for bypassing the firewall for Secure FTP. The problem is that once I configure the second adapter (en1)with a real world address, subnet, and default gateway the server is immediately disconnected from the internal network. Both cards are using the same hostname…I don’t believe there is any way around that. Any ideas? Thanks!!