If your developer portal is hosted on Pantheon and you already have access to pantheon dashboard you can upload your SSL certificates yourself.
Here is the documentation link : http://apigee.com/docs/developer-services/content/using-ssl-portal
If you need access to pantheon dashboard please open a support ticket and we will add you to the dashboard.
Do we need to create csr using openssl and then get crt from the SSl CA?
Can csr be created on any system?
Are these steps are valid as of today.
I am not seeing the Text boxes for uploading SSL certificate and Key now