How do I use both Markdown expressions and HTML styles?

[NeoCompanion-max]

When I use # Heading, it gets replaced with <h1>Heading</h1> and displayed on the screen.
I want it to be displayed as <h1># Heading</h1>, and I want to be able to edit the # symbol at the front.
Also, when I execute getText, I want to retrieve it as # Heading.

I've tried modifying renderHTML and renderText, but I haven't been able to achieve the desired result.