Mario,
I've gotten this to work through a slightly different process. I've added a UI Action button on the form that when certain conditions are met (i.e. Priority 1, etc) a 'Send Email' is shown.

When this button is clicked it throws a pop-up which contains the exact information that will go out in the email notification. There is also verbiage that states "By clicking OK you are attesting to the information that is going out in this email, please hit cancel if changes need to be made." The pop-up itself is made of HTML is virtually identical to the email that gets sent out.

Once the user hits the OK button an event on the UI action kicks off the email notification and populates the email notification based on the pre-filled fields on the incident form.