SLA Alerts/Breaches to HTML Emails - Tailoring Notifications

Hi Experts,

What I am trying to accomplish seems fairly simple in concept, but is turned out to be more difficult than I previous thought. I am trying to create SLA Alerts/Breaches HTML Emails for each of the Service Modules (IM, RF, ChM, PM and SD). These Alerts are following the SLM SLOs I have created. (SLA - 25% for example)

Similar to the built in, notification SLA Alert_1 which sends a very ugly Plain Text Email for probsummary (IM), following Alert Msg Class 18

Now a couple questions, as the SLA Alerts seems to use the Alert Msg Class, can I replace this using HTML Template and somehow configure it that way or can I add the Arguments/Conditions to call the HTML Templates?

Am I completely neglecting something that I should be configuring on top of this? (Messages, HTML Templates, Notifications?)