Question regarding OmniORB SSL example

We are currently trying to switch our usage of omniORB for CORBA
connections against a jacORB where we would like to use CORBA SSL. We
use CORBA SSL since several years with jacORB alone and its
configuration is very different from how omniORB allows to configure
it. I looked at the ssl_echo example, and tried to compare it with
section 7.8.1 of the omniORB.pdf which explains how to create the
necessary .pem files using openssl. The point I'm currently struggling
with, is how the root.pem corresponds to the descriptions in 7.8.1. My
understanding is that the client.pem (and server.pem) are the result
of the process that is described by

"To make a single file containing both the key and the certificate,
suitable for use in omniORB, concatenate the key and certificate files
together. [..] If need be, create more certificates for servers and
clients in the same way."

But where was the creation of the root.pem described in this section?
Is this the same (or a copy of)