Customization of Automation webhook payload "shape" or "template"

[Justin Warwick]

Particularly in Server edition of JIRA with Service Desk module, I am very interested in using the Automation feature's "Webhook" action to send a JSON payload upon certain state transitions. However, I would like to customize the "Shape" of the JSON payload. How can we do that?

Scenario: I want the webhook to consume one of Microsoft Teams' channel notification webhooks that expects a very specific JSON payload format (or "Shape", if you prefer):

https://docs.microsoft.com/en-us/outlook/actionable-messages/message-card-reference

Some interesting leads, but I did not see a definitive answer:

https://community.atlassian.com/t5/Answers-Developer-Questions/json-payload-format-for-board/qaq-p/571255

https://developer.atlassian.com/server/jira/platform/webhooks/#Webhooks-configureConfiguringawebhook