Select default signing certificate
You if you have more than one Internet certificate, you can select which one to act as the default signing certificate.
If you only have one Internet certificate, it automatically becomes your default signing certificate used when you want to sign Internet-style (S/MIME) mail sent over the Internet or to other IBM® Notes® users. If you have more than one Internet certificate and you have not manually chosen one of them to be your default for signing, the last one which was added to your User ID becomes the default.
Once you select an Internet certificate to use for signing Internet-style mail, click OK.