Verify if you have a third-party certificate
Applies To: Windows SBS 2008
Devices that are based on Windows Mobile 6.0 ship with a variety of trusted root certificates from major certificate vendors. If a third-party security certificate is already in the certificate store for Windows Mobile, you may not need to install a certificate on the device.
Contact your network administrator to verify that the certificate chain of the third-party certificate is validated by a provider that is listed on the certificate store. To view a list of certificate providers for devices that are based on Windows Mobile 6.0, see the Microsoft Web site (http://go.microsoft.com/fwlink/?LinkId=144437).