Victor,
I've installed a mail server (hMailServer) on the same server as NetXMS to allow me to capture the smtp conversation.
Funny is that sending mails through this mail server works fine. However since our Exchange settings didn't change and that problems started when upgrading to 1.1.4, taking into account no change was made to the sending mail function, could it be the problems has to do with character sets (compilation)? I'm asking this as the Event Browser shows Chinese chars where the e-mail address should show, this it typical with Unicode related issues.
As for me, I'm going to keep using the local mail server as it presents several advantages over sending mail through the Exchange server.
Dan