a background email is not a built-in possibility of GuiXT. You need to implement
an ABAP function module, an .exe program or a dll that you can call from GuiXT.
the ABAP function: I do not know of any BAPI that sends an email, but perhaps
one exists. To implement the function module on your own, see the SAP standard
program BCS_EXAMPLE_1 for an example. In your script you use the
"Call" statement to call the function remotely.
an .exe program: it can be implemented in any technology. In VB.NET it is
relatively easy; use
Dim Smtp As New SmtpClient(...)