I know how to use the ExFeHttpsOn.dll filter to set up Outlook Web Access (OWA) behind a Secure Sockets Layer (SSL) accelerator. However, why doesn't Outlook Mobile Access (OMA) work after I implement this configuration on a new Exchange Server 2003 front-end server?

You might encounter problems when you attempt to off-load SSL processing for OMA because Microsoft doesn't officially support this configuration. That doesn't mean you can't make this configuration work; merely, the company hasn't performed the work necessary to qualify and test OMA behind various third-party SSL accelerator solutions. For a good overview of troubleshooting SSL, see the Microsoft Webcast at http://www.microsoft.com/usa/webcasts/ondemand/2099.asp.