So going though v7, v8 and v9 of the certificate guides I continued to have some issues getting the certificate to work and the steps never included ways to add subject alternative names. Upon further research I have identified a good step by step to replace the trend micro DSM certificate and include subject alternative names using a Microsoft certificate authority.

1. Stop the “Trend Micro Deep Security Manager” service
2. If not already created, create a folder on the root of C:\ called “certs”
3. Go to C:\Program Files\Trend Micro\Deep Security Manager and create a new folder called …