Calling a stored procedure after copying from CSV to Azure DB table

Question

I have a need to copy the data from 3 CSV files into 3 staging tables, and then call a stored procedure to move the data from the staging tables into the line of business tables.
Copying the data from the CSV files into the correct staging tables isn't a problem.

But how to call a stored procedure once the third saging table has been populated successfully?

From the Azure documentation it looks like I add a new Activity of type SqlServerStoredProcedure.  When I follow the example in the docs and try to deploy the ARM template I get an error message saying:

"New-AzureRmResourceGroupDeployment : 15:55:54 - Error: Code=InvalidTemplate; Message=Deployment template parse failed: 'Could not find member 'typeProperties'
on object of type 'TemplateResource'." not found."

The section of my ARM template that refers to is:

        {
          "name": "[variables('activity_call_proc')]",
          "type": "SqlServerStoredProcedure",
          "apiVersion": "2017-09-01-preview",
          "typeProperties": {
            "storedProcedureName": "[parameters('db_proc')]"
          },
          "linkedServiceName": {
            "referenceName": "[variables('azureSqlLinkedServiceName')]",
            "type": "LinkedServiceReference"
          }
        }

The typeProperties clearly *are* there, so the error message must mean something else.

How do I get my pipeline to call the stored procedure on the Azure SQL db referenced in the linkedServiceName?