Oops, sorry. Each outgoing message would need to be tagged.
Very bad idea. You should never use a custom form to send mail to external recipients. It will cause frustration or problems for any recipient that doesn't use Outlook. Not something you would be expected to know as a forms newbie, BTW.
A better solution might be to put some client/property tag in the message itself, either with signatures or, if you're using Word as the editor, with a Word macro.

Signature
Sue Mosher, Outlook MVP
Author of Configuring Microsoft Outlook 2003
http://www.turtleflock.com/olconfig/index.htm
and Microsoft Outlook Programming - Jumpstart for
Administrators, Power Users, and Developers
http://www.outlookcode.com/jumpstart.aspx
> Oops, sorry. Each outgoing message would need to be tagged.
>
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>> > Clearly I'm a newby at this so I apologize for the blatant stupidity of the
>> > question.