Just a suggestion, as I'm not really sure if this will work, but connect the device to Desktop Manager (with the same version handheld software installed on that PC) and remove the Root Certificates. Let the device reboot itself then readd them. Who knows, it might work. As for the other question, you can likely install the certificate to that same PC and use Certificate Synchronization (optional component during Desktop Manager installation) to synchronize that certificate to the device.