I would like to suggest to all coders who provides MODx with a stuff that they should avoid direct calls to mail() function. MODx has a well worked out class PHPMailer which provides with a flexible interface to mail system. The mail() function itself "looks very innocent" when you build the site in a developer domain on your own server where all configuration details are under control. But try to transfer it to the hosting domain where guys turned off mail() for security reasons... It is a nightmare to collect and rewrite all those dispersed mail() calls into the communication, for example, via SMTP.
I have patched on my own Jot and Weblogin snippets where I have rewritten crucial calls to mail() into the calls to PHPMailer class. Armand Pondman pledged to include my work into the further releases of the Jot. I believe that the coding the communication in MODx should always be done via PHPMailer class. The code is longer but it provides with a better portability - you need to set only several configuration vars in PHPMailer class and an appropriate communication (mail(), SMTP, Sendmail, QMail...) will extend onto the whole MODx.
Patched Jot and Weblogin might be found on my page:
http://setpro.net.pl/software/modx-stuff#attachments.