WDE 8.5 Customization, customize ToolbarInteractionBarRegion

Hi all,

I have to customize the WDE 8.5, in details i have a requirement to add a counter in the ToolbarInteractionBarRegion to evidence the Hold time. please find below and easy mockup of what i would like to do…inside the green box the counter to add

https://lh3.googleusercontent.com/-_pM3FWke9ZE/VV3b2IRbblI/AAAAAAAAXEc/NVYc4Jy8aaY/w577-h91-no/CustomToolbarInteractionBar.png

Is it possible? if yes can you help me?
Thanks,

Carlo