Remote Smartlist moderation

I'm attempting to maintain a moderated Smartlist from a Windows PC (ie via e-mail). I've built a small SMTP client (in Delphi) that can massage the message header to successfully send X-Commands. But so far I have no luck in resending an 'Approved:' message back to the list so that it is distributed. Does anyone know what header lines need to be present, or if there's already a PC program that can do this for me, Thanks, Peter Wiltshire Peter Wiltshire KIS Software, Amsterdam (NOTE new e-mail is Peter@kissoftware.nl)