AvalonEdit : how can change backcolor and tag in AvalonEdit by SyntaxHighlighting?

I am developing an application and using ICSharpCode.AvalonEdit, I want to show piece of text text on it . The text is contain of some usual text , list test or code tag, a good sample if i want say the text is similar stack-overflow tags In continuous I will put an example, my problem is that how can i change <li> and <Ul> tag to DOT or how change background color also clean the <code> tag. example

some text

<ul><li>a</li><li>b</li><li>c</li><ul>

some other text

< code> piece of c# code int i=0; for(int j=0;j<10;j++) i+=j;< /code>