Start an Automation Runbook with Parameters from a Power App Button

[AndrewX]

I have the following code for a Button OnSelect function.  The Azure Automation Runbook has 3 required paramters with matching names to the record below.

When i click the button, the automation runbook fails because "Cannot process command because of one or more missing mandatory parameters:"

Any idea how to pass parameters to a runbook in a PowerApp.  PS.  I want to do this directly in a PowerApp button, NOT trigger a Flow AND THEN trigger a Runbook.

Set(AZAutomation,AzureAutomation.CreateJob(
    "nnnn-nnnn-nnnn-nnnn",
    "nnnn",
    "nnnn",
    {
        runbookName:"MailboxManagement",
        wait: true,
        body: JSON(
            {
                param1: ComboBox1.Selected.UserPrincipalName,
                param2: ComboBox2.Selected.UserPrincipalName,
                param3: DropDown1.SelectedText.Value
            }
        )
    }
))

[#2]

@AndrewX hey, did you ever manage to solve this by any chance? Thanks