Thank you for writing in. Currently the only way to connect to your workspace is via the ports 8080, 8081 and 8082 (more information about multiple ports here. Each of these ports are routed through an HTTP proxy that forwards traffic to your workspace. If you enable MongoDB to listen on one of these ports, you should be able to connect to it externally. However, the protocol has to be HTTP based, and not a custom protocol.
I hope this helps.