Stapling documents in a workflow

We need to staple documents in a workflow and we had thought of using the web service with endpoint "/FileCabinets/{{DocumentTrayId}}/Operations/ContentMerge" that can be used to staple/unstaple/clip/unclip.
This endpoint has existed since at least 2021, but it is not available among those displayed by the standard Docuware web service in the workflow. Tested on 7.9 on-premise and 7.10 cloud.
Why is it not available in the dropdown?

In the end, to clip we use the endpoint "/FileCabinets/{{FileCabinetId}}/Operations/ProcessDocumentAction" with parameter DocumentAction = Append

Is there a way to staple documents in a workflow? (without Stapleware)

Thanks in advance

Dear Jesús Fernández! It looks like the Community cannot answer your question. That's why we have opened a Support Request with the Number SR-244690-M1W1D for you. A Software Support Specialist will contact you directly to follow up. We will update this thread with the solution as soon as we have resolved the Support Request. With best regards, DocuWare Support Team