Use this script to quickly create a new certificate request based on a .INF file using some common parameters found in your exchange environment
Save this script to a folder you wish to operate from, this same folder will contain the generated .INF and .REQ files
Run this script from the Exchange Management Shell (or from ISE/Powershell, just make sure to run add-psssnapin *exchange* first)
Navigate to the folder containing the script and execute (.\Generate-CSR.ps1)
It will then collect some basic information from your Exchange environment, create a .INF (template) file, then generate a CSR against that template.
(From Powershell),
Add-PssSnapin *Exchange*
SL C:\Certificates
.\Generate-CSR.ps1
Once run navigate to the c:\Certificates folder and open the .req file (then complete through your CA/PKI team)