RenderDocument "onMount" Sequential using DataSource items??

I have a datasource for my APL document:

{  
    "templateData": {    
    "type": "object",    
    "properties": {      
    "items": [        
    {
          "premiereDate": "Wednesday, April 30, 2008",
          "type":"Movie",
          "name": "Iron Man",
          "index": "",
          "source": "https://example.com/service/Items/16318/Images/primary?quality=90&maxHeight=1008&maxWidth=700&",
          "id": 16318
     },
     {
          "premiereDate": "Thursday, June 12, 2008",
           "type":"Movie",
          "name": "The Incredible Hulk",
           "index": "",
          "source": "https://example.com/service/Items/16507/Images/primary?quality=90&maxHeight=1008&maxWidth=700&",
          "id": 16507
       }
       ]
     }
}

I'm trying to access my datasource info in the document "onMount" event.

I am using "SetValue" on the footer hintText to let users know the speech commands available to say. I'm cycling through the possibilities by using data from my dataSource.

Example: "Try \"Alexa, show the ${data.type} ${data.name}\""

However, when using a "Sequential" in the onMount event, I can't seem to set the "data" attribute to the datasource payload.

Is it possible to load the dataSource into a sequential command, or am I missing something? or am I completely wrong?

Note: I am using APL 1.1 (hence the use of the "payload" param on the mainTemplate object.)

My Render Document has a footer with hint text, it looks as follow (some items removed except for footer):

{
  "type": "APL",
  "version": "1.1",
  "theme": "dark",
  "import": [ ],
  "resources": [ ],
  "onMount": [
    {
      "commands": [
        {
          "type": "AnimateItem",
          "easing": "ease-in",
          "duration": 1020,
          "componentId": "hint",
          "value": [
            {
              "from": 1,
              "to": 0,
              "property": "opacity"
            }
          ],
          "screenLock": false,
          "delay": 5000
        },
        {
          "type": "SetValue",
          "property": "hintText",
          "value": "Try \"Alexa, show the ${data.type} ${data.name}\"",
          "componentId": "hint",
          "screenLock": false,
          "delay": 0
        },
        {
          "type": "AnimateItem",
          "easing": "ease-out",
          "duration": 1020,
          "componentId": "hint",
          "value": [
            {
              "from": 0,
              "to": 1,
              "property": "opacity"
            }
          ],
          "screenLock": false,
          "delay": 2500
        }
      ],
      "type": "Sequential",
      "repeatCount": 5,
       "data": "${payload.templateData.properties.items}"  <---Not loading DataSource!!
    }
  ],
  "mainTemplate": {
    "parameters": [
      "payload"
    ],
    "items": [
      {
        "type": "Container",
        "items": [
          {
            "hintText": "",
            "type": "AlexaFooter",
            "position": "absolute",
            "bottom": "1vh",
            "id": "hint",
            "opacity": 1,
            "disabled": false
          }
        ],
        "width": "100vw",
        "height": "100vh",
        "id": "primary",
        "opacity": 1,
        "disabled": false
      }
    ]
  }
  "commands": {  }
}