Thanks for evaluating SyntaxEditor. We include a free VBScript language definition with SyntaxEditor that does basic syntax highlighting. You can see that shown in the SDI Editor demo if you go to the Languages menu.
SyntaxEditor supports the creation of advanced editing features for any custom language. While we don't have an advanced add-on for VBScript, if you wanted to add more advanced features you definitely could. Some feature areas are easier than others, but our Getting Started series of samples does a great job of walking you through building a complete language with automated IntelliPrompt features and more. So it's a great resource for learning how to add various language features.