Question : OWA High Availability

I have Exchange 2003 running OWA and have created an internal DNS A record that allows internal access to OWA. However, if the VPN Tunnel between one of my remote offices goes down the users in that office cannot access OWA. I have tried creating two A records with one pointing to the internal IP address and one pointing to the public IP address. I have a Cisco ASA 5520 firewall, which prevents inside access of outside natted IP addresses. Any ideas on how I can provide High Availability for OWA at my remote sites?

Answer : OWA High Availability

if you change the external name and configure the internal name to "not take" the proxy server is could work!
The problem is the dns record which still points to the internal ip even when the vpn tunnel is down...in this case...internet!!!!