We have this issue solved in the MAPI releases. However, we might soon do a pre-mapi release with this same fix as it has been affecting everyone from sending this to Gmail.
We now provide a field that allows you to specify your FROM address for all system messages that would experience this issue, like event notification messages, password resets, anything else from the system.
Matt Petty
Software Developer
SmarterTools Inc.
(877) 357-6278
www.smartertools.com