The extension properties for this object class.
[Visual Basic 6.0] Property ExtensionProperties As IPropertySet
[Visual Basic .NET] Public ReadOnly Property ExtensionProperties As IPropertySet
[C#] public IPropertySet ExtensionProperties {get;}
[Java] public IPropertySet getExtensionProperties() throws IOException, AutomationException
[C++] HRESULT get_ExtensionProperties( IPropertySet** extProps );