Dragan,
>Tried that first, but in my case I must go through the login, which simple SendMail() won't do. I'm getting the '550 we do not relay' error message when I try that.
You can't set the username and password properties on wwIPStuff to match a valid combination for Exchange?
Or maybe you just need to get the administrator to change the relay settings to allow relay from a particular internal IP or IP range, or a certain internal user or group. I can't point you to the exact way to do that today, but it's certainly configurable within Exchange.