We are migrating from in house Exchange 2007 to Office 365. Our VB based order management app uses SMTP to send emails to customers. Instead of doing a ton of recoding to use a new SSL local component, are there any issues with just setting up a local SMTP relay to Office 365? If we have the local SMTP relay server, than we can stick with port 25 and non-ssl. The relay would send SSL however to the Office365 SMTP server.
Environment is Windows Server 2008 R2, which the VB based app runs on.