One of my customers was creating certificate requests programmatically with CertEnroll and a code like the following: How to create a certificate request with CertEnroll and .NET (C#). He wanted to set Friendly Name for the enrolled certificate. Friendly Name is a property (and not an extension of the certificate) that can be set on the enrollment object itself:
You should set this property before calling Enroll method.
I hope this helps.
Alex (Alejandro Campos Magencio)