How to create date based card on dashboard using Streaming Dataset

Hi PWRBI family,

I created a Power BI dashboard that's using data coming from an Azure's Stream Analytics job. The use case is simply a stream of stock market buys and (i.e. number of trades) and total price paid for all trades within a Hopping Window.

I wanted to add a tile which references the max date of a date-time column within the dataset.

I can't seem to achieve this, any clues?

Steps I have followed are below.

Example Stream Analytics job output query used with the stream:

SELECT
    sum(Trade.Quantity * Trade.Price) as TotalTradedAmount
    , count(*) as TotalTradeCount
    , System.Timestamp as WindowDateTime
    , Max(System.Timestamp) as LastRefreshed

Example of my end dashboard:

I would like to add a Last refreshed card which shows the max date of place trades, similar to card “A” below.

A) Example of my end dashboard minus "Last refreshed card"

The stream comes through ok via the dataset (see image labelled: B) on Power BI service.

B) Screenshot of Power BI - Data set field definition

However, when I [Add a new tile], select [Custom Streaming Data] (see image labelled: C), select the card visual and try to select the [LastRefreshed] data point, it doesn't appear within the available [Fields] dropdown (see image labelled: D)

C) Screenshot of Custom Streaming Data card usedD) Screenshot showing available fields options within Tile > Card dropdown field