I find this kind of workflow easier to implement using the graphical Business Process (BPL) editor.

In BPL you'd use a Call element to invoke your Business Operation asynchronously, and a Sync element to catch the response message when it's sent back later.  You can do other processing between those elements, such as making other Calls.

Here's a link to documentation that provides an example of making 2 concurrent async calls to Business Operations, waiting for both of them to return, then deciding what to do next based on content of the responses.

https://docs.intersystems.com/iris20252/csp/docbook/DocBook.UI.Page.cls?...

If you prefer code, you'll need to implement onResponse in your Business Process.  That will be called by the framework when the async response comes back from your Operation. I don't think you'd want to branch back to onRequest from there however.  You'd just put the logic to handle the response in onResponse.

You have your Business Operation class so you can ignore the X12 Output and Workflow tabs. Those are helpers for cases when you're using built-in Operation classes.  They help you select the right class even when you don't know its name.

Your code references your Adapter, so there's nothing you need to do in this wizard to select EnsLib.NullAdapter. The code is also where the Request and Response classes are specified, so you don't need to do that here either.

You can give it a meaningful name, or you can leave that blank and the class name will be used for the Operation name.

After adding this Operation to your Production, take a look at its settings.  You may want to adjust things like Pool Size.