The control fills out Headers each time any of the other properties for that ediattachment are changed.
The control fills out AttachmentHeaders each time any of the other properties for that ediattachment are changed. If additional headers are needed they should be appended after all the other propertys for that ediattachment are set.
The AttachmentIndex parameter specifies the index of the item in the array. The size of the array is controlled by the AttachmentCount property.
This property is not available at design time.