Would prefer not to send through gmail. Your suggestion for an un-guessable address is a great idea though, way to think outside the box! I'll let you know how it works but my only concern is if the weird address causes problems with spam filters, etc.
Plesk is set up to forward incoming mail to my gmail account. I've configured an account in gmail to "Send mail as" so that email sent from my gmail account is routed through my web host's SMTP server. However, this only works when "Mailbox" is checked in the Plesk mail settings. I prefer...