Sorry - maybe it wasn't clear.
Custom domains are not supported in the Cloud UI because our cloud does not support custom domains. Since Hybrid is an extension of the cloud, and uses the cloud UI to configure it, those features are not enabled in the UI, though they will work in a hybrid environment, since they are disabled at the gateway level.
As I said, we may split out UI options for Hybrid users in future. But currently it is the same UI for both classes of users.