How to use IconGutterMark?

Hi

I'm interested in plugin development for resharper and I tried to convert the cyclomatic complexity power toy to 4.5.
I got it to work however I noticed two unused classes wich are derived from IconGutterMark.

Can anybody give me an hint where I could use them so they are displayed?

And if anybody has a link providing some good information about plugindevelopment for resharper let me know.

Best regards,
Sven