Does anyone know if there's a way to configure Exchange 2010 to generate OOF replies in HTML instead of plaintext? My problem is that I have a number of clients on Outlook 2003 in addition to 2007 and 2010. For 2007 and 2010, they can of course create an HTML OOF message, so they're set. However, the OOF created in 2003 is plaintext only, which is causing some problems with signatures, etc. Is there any way to force HTML for all OOF's via a Transport Rule or something similar? Thanks!

With Outlook 2003, the only way I can think of doing this would be to create an auto-reply rule that replies with a HTML template message rather than using the built-in Out of Office. Auto-replies are a bad idea though of course. Since you are using Exchange 2010 however, why not have them use OWA 2010 instead to create their OOF messages?