I think a better aproach would be to create a subclass of mmCheckedListBox and override the appropriate methods to do what you want. Probably the OnBind() event would be a good place to start. First I'd look at the mm source code to see how the framework currently supports the data binding for that control and if you don't like it you can override the behavior.

I've done this on the asp.net side but I copied the code and changed it where I wanted instead of subclassing. Probably not a good idea and I can't remeber now why I did it that way.