The Oberthur ID-One Cosmo Token device has been tested and recommended by YAP* as it has been found to work properly with the public key infrastructure (PKI) of the HERMES gateway. This particular device has an installed base of several thousand units in Greece.
If you want to obtain digital certificates from the Certification Authority of the Greek Public Sector (APED), you should follow the steps as described on the YAP website.