According to the Excel manual, there are three variants of the Copy()
method that applies to Chart objects (and others):

Syntax 1: expression.Copy                - copied to clipboard
Syntax 2: expression.Copy(Destination)   - copies range
Syntax 3: expression.Copy(Before, After) - duplicates the chart

I can create an Excel application and call other methods, but when I try
to get syntax 1, by calling

 chart.Copy(System.Type.missing, System.Type.missing);

it invokes syntax 3 (and duplicates the chart), probably because the
Before and After parameters are optional.  How can I tell C# I want to
invoke the syntax without parameters?  How can it tell the difference?

Dev Studio 2003 + Office 2000.

  Oliver