It's not very difficult on the BCM50 side. We had other techs handle the CS1000 side. They always blamed me first, for 1 way speech or calls not completing and 95% of the time it was a routing entry missed on their side. So, I will be of no help to you.
You just need to make sure you choose Gatekeeper Resolved and precede the Alias name with, NAME: The rest is basic VoIP routing. The advantage is you don't have to build any endpoints, that's all done by the Gatekeeper.
Adversity is Opportunity