I had a similar issue a few years ago. Here is how I got around it.
MailToString = "mailto:" || emailAddress;
Web( MailToString );
Thanks for this I had tried this also.
Just I was trying to Script in order to send out e-mails automatically , web mail function I believe you still have to press the send button.
Also would like to add attachments which cannot be done in the web mail function, I believe.
Tomorrow I am going to install "Outlook" to link up my g-mail account then try the mail () function.
Let you know how I get on.