Hi Victor,
Please confirm which version of Gateway you are running. If it's 9.3, there are a few websocket-related bugs that were fixed up in cumulative releases ("CRs") that you may want to look into as in some cases it affected the way the connection was made (or rather a lack to create a connection successfully). Documentation referencing that is here for your reference: Resolved Issues - CA API Gateway - 9.3 - CA Technologies Documentation
From the documentation, I saw a note that reads that if an existing Websocket connection has changes made, the Websocket server on the Gateway is restarted, so it should do it all automatically for you I would think. Ref: WebSocket Connection Properties - CA API Gateway - 9.3 - CA Technologies Documentation
With that said though, I do see that a restart is needed after setting/changing any cluster-wide property related to websockets, which might imply a restart really is needed for a websocket connection. Ref: WebSocket Cluster Properties - CA API Gateway - 9.3 - CA Technologies Documentation
Unfortunately I don't have a lab available where I could quickly test this, so my input so far has just been what I've observed reading through the documentation.
If you can confirm the Gateway version though, this may be relevant in case it's a bug. As a side note, no matter what version you are on, I'd recommend making sure you're on the latest CR. ;-)