USING FACE IT - adding the option of seeing heart rate on the watch face

I want to create my own watch face but I need to be able to see my heart rate on the watch face

The options on Face it only have steps or distance and I have been unable to find a way of changing them.

I have downloaded a couple of watch faces which have given me the option to change what value I can see on the watch face so I am surprised that Garmin has not thought of this for their Face it.