Add new/custom pane in compose email window

[Irfan]

Hi,

Is there a way to add a new pane like spell checker, resource or Clipart
pane appear in compose email window?
There two Interfaces Panes and FormDescription, will this provide any help?
Please guide me how to add custom pane.

Thanks,
Irfan

 

[Irfan]

Here is more detail what I want to add in compose window.
I need to add my controls at the position displayed in image
http://www.infolink.net.pk/images/pane.jpg