Extensibility - Drawing On Code Window

[Mythran]

I remember seeing a web page that described how to draw images onto the
code-window's background in Visual Studio. What I want to do is simpler (I
would hope). Simply put, I want to put a silver rule line down the 81st
column on the code window. I would like to do this using C# and understand
that I may have to use C++ to do it (I remember something about not being
able to do one of the things that is required to do this using C#).

I do have the VSIP SDK and know that I probably need to use it to do this,
but still need help in getting started. Any pointers/suggestions are
welcome :)

Thanks,
Mythran