Email size restriction, user notification

Guys, we’ve just migtrated from Novell to a MS Exchange/Outlook 2007 environment. We’ve locked Outgoing and incoming mail size’s down to 10mb.

The issue I have is this: When you send an email over the 10mb limit it simply sits in the users outbox. If you click on send recieve then it will give a send error report.

Is there a way to force this error report to come up without having to click send recieve? If not, is there a way to notify the user that their message is not being sent?