Extending Visual Studio to place marker in the margin

Hi,

I would like to extend Visual Studio to place the marker in the margin(like breakpoint marker) for a given set of line numbers for the active document in C#.NET and also clearing off the marker.

I am basically looking for controlling the placement and clearing of the marker programatically using C#.NET.

Please help me how to proceed with this.

Regards,

NeelAk