I use SSLs.com as a registrar, and they resale SSL Certs from a number of other companies, including Comodo. These are the steps I went through to set up a PositiveSSL’s SSL cert.
First, purchase the certificate, follow the steps on their site, and you should soon get an email with your PositiveSSL Certificate. It contains a zip file with the following:
- Root CA Certificate – AddTrustExternalCARoot.crt
- Intermediate CA Certificate – COMODORSAAddTrustCA.crt
- Intermediate CA Certificate – COMODORSADomainValidationSecureServerCA.crt
- Your PositiveSSL Certificate – www_example_com.crt (or the subdomain you gave them)