Caller Id parameter ignored when using the RingOut API - am I utilizing the parameter properly?

We are trying to set the outbound callerid number using the RingOut API. If I view my user record directly in RingCentral I can change the caller id number under RingOut from Web and that works fine.

The issue I'm having is that I'd really love to be able to set it dynamically, and I was excited to see that the RingOut API documentation clearly states that there is a Clid parameter for setting it. Unfortunately, that parameter seems to get ignored. Am I missing something?