How do I add special characters to the default Special Characters dropdown?

How do we add a new special character to the Special Charaters dropdown in Draw > Text > Note .....  Command box?  We have a Unicode charater we use a lot (203B) that I would like to add to this list.  I have not found an easy way to add this since there is no Alt+ command for this and the MS Windows Alt+X after doesn't work either.  IT would be most handy to be able to augment the list of standard items with user specific.  Thank You!