The first thing is to check with (plead with) your IT folk to see if the IMAP gateway on Outlook\MsExchange is set up.

I have 23 Pegasus users that I inherited that are getting mail from our ISP just fine.  But now some want to use Outlook and most don't. The ones that do want to use Outlook want to be able to get to their saved email from Pegasus. I have set up Mercury on a spare server but need some direction from here. I am not having much luck with Help and the forums because their problems are way beyond me. If someone can point me in the right direction I would appreciate it. Thanks