This property determines the authentication user name to be used
when accessing secured web sites.
For example, you might set this property to "MyServer\Steve" to
authenticate as Steve when accessing a particular web site.
This property needs to be used in conjunction with the LogonPassword property.
ABCpdf is a user like any other user. When it is logged in, it
stays logged in until the session times out or until you explicitly
log it out. So if you wish ABCpdf to log on as a different user,
you must ensure that it is logged out first.