The ShellAPI to do this is pretty much a lucky hack that the OS provides to feed data to another program via parameters.
If you want to build sophisticated emails with HTML content and attachments you need to use an SMTP client to send emails.
Something like wwSmtp will do the trick:
http://www.west-wind.com/webconnection/wwClient_docs?page=_s9001zxj2.htm
This is part of West Wind Client Tools or West Wind Internet Protocols or West Wind Web Connection.
+++ Rick ---