_az,
Thank you so much for your help. I was able to successfully create the mydomain.crt, mydomain.key, mydomain.csr an account.key files. However, when I tried to use openssl to generate the .pfx file, I got the error below. Yes, this is more of an openssl question, but it is also related to SSL on ISS server. I hope you have the answer for this question.
PS C:\OpenSSL-Win64\bin> openssl pkcs12 -export -out mycert.pfx -inkey mydomain.key -in mydomain.crt
No certificate matches private key
PS C:\OpenSSL-Win64\bin>