Yes I did look at those links, hence my post.
The only explanation for the Paramater is
instance
A String value used to specify EASendMail Service instance.
and the example shows simply
hres = oSmtp.SendMailToQueueEx( "myinstance" )
But how do I know what string vaule I need to pass for any particular installation?
How do I know what my "EASendMail Service instance" is?
Passing an empty string to SendMailToQueueEx seems to work, so what is the difference detween doing that and passing some other string ?