Hi @David_Pincheira!
You can find this icon in WhatsApp Chat widget:
However, there is no such an icon in All-in-One Chat. I am so sorry!
Unfortunately, at the moment, there is no option to upload a custom icon to the widget.
We totally agree that this functionality would be really useful and we have such a request in our Wishlist. Please vote for this feature to get a notification upon its release 