From a C# automation app how do I zoom a dgml view to 100%.

I have looked at all the .vsct files and cannot find the appropriate control. I have created a dgml file in this C# app and want to save the image an use it. Visual Studio ignores the ZoomLevel property in the dgml file and displays the image to fit the window which is too small to see the text in a large diagram.

Thanks

Tom G.