The BMP does not cater for adding buttons directly to existing forms, you will need to manually create a button yourself. In order to accomplish this, you will need to first create a radio form element within the chosen BMP form.
Once that has been saved, you will then be able to target the new form element using the data-name element and replace it with a button using the following jQuery code.
$(“[data-name=’<name of radio element>’]”).replaceWith(“<button>Button Text Here</button>”);
Then it’s just a matter of using inline styles to position, and style the newly created button.