Whilst I thought I was there, I actually have hit another snag re the actual certificate.
My starting point is that I can access the nettalk webserver app via my URL using
https://sub.mydomain.com, with the webserver using port 443 and SSL and using the supplied self certified certificate.
I then used the CreateCertificateSigningRequest.bat batch file to generate a request and pasted the text of that request into an online SSL company's form (I am trying RapidSSL free 90 day trial cert).
After verifying info and accepting email address link, I received an email with text of a "Web Server Certificate" and an "Intermediate CA".
I copied ForRealCSR.crt that had been generated into \web\certificates folder and renamed it Settings.crt, overwriting the old one.
Now I am faced with the Settings.key file which contains -----BEGIN RSA PRIVATE KEY----- ......
How do I generate the RSA private key text from where I am now?
Any guidance much appreciated!!