Mmmm... personally I would put it, precisely as it is written in your own post to me, that is with the square-bracketed prefixes and postfixes for color and size in a Notepad-file of my own (or in a private mail of my own to this forum), and use that file to copy-paste from to this editor for the forum (that underneat is much like Notepad).
Alternatively, if you have a way and understanding of keyboard macros for your system, you could put it there. (But this depends so much on your own system it won't help much to try to explain it if you are not familiar with the concept of keyboard macros to start with.)
Explanation (partial): The ASCII 3 trick uses the fact that this editor displays the low ASCII codes nrs 0 to and including 31. Many more fancy editors don't, because in early days these 32 codenumbers encoded machine-instructions. So in this editor it is like a typed letter, after you got it with ASCII 3 on your screen, and this is why my above recommendations probably also will work for you.
Personally, I don't use icons in mails, and haven't figured out yet how this editor does what it is supposed to do (it is not very well programmed, which I know because I know what the programmers have used, that I can program myself). My own site has its own icon, and I know how to make those (knowing how to program, having an icon editor etc.) so I know a heart icon may be made for websites, but I don't know how to integrate that into this editor and its iconlist.
I hope this answers your questions. My own approach would probably be - if I were to use a red 5 point star often - to put it and its pre- and post-fixes in a file and copy/paste that, and/or else simply to do it by hand from memory if I'd use it occasionally.
P.S. Having just uploaded this, and seeing Kim's post, it MAY be the case that the WYSIWYG settings she recommends MAY do the trick as well.