If a user CCs someone, their CC shows up in the "client-defined cc" field. If they do so and later call and ask us to add someone on their CC, we can modify it for them. However, if they haven't CC'd anyone, the field doesn't show and we have to add them to the Tech CC field, which doesn't show to the client (so they think we didn't CC the other people for them).
Is there any way of adding a client CC through the web interface?
There doesn't seem to be. I almost think that there is a 'list recipients' option hiding somewhere in WHD that might show in the emails that are sent, but in the web interface there doesn't appear to be any way to do this.