How do I modify page content using Confluence Automation workflow

[Niels van Dantzig]

I want to post updates on a Confluence page based on triggers from Microsoft Power Automate when data changes in a SharePoint list. 

For this objective I have created a Power Automate flow with a HTTP call to the webhook of my Confluence space. 

Additionally, I have created an automation in Confluence to execute when the webhook is called.

I can send data over from Microsoft Power Automate in the body of the call. 

However, there the action the flow performs is to create a new page, but there seems no way to pass on the data in the body to the content of the page. It will just be an empty page (or based on a template).

How can I exactly post some content on Confluence or update existing content on Confluence with this set-up?