How do I default DESKTOP SECURE (using my Enterprise email service) as the default vs my personal MSN. When I compose a new email it says default in the from line but as soon as i select a TO email address, it changes to my msn send service-- not what i want- I want the enterprise email service to be the default and change it manually if I prefer the MSN email service.

Options > Advanced Options > Default Services > Messaging (CMIME) = Desktop

These Advance Options were, have, and are set as described--DESCKTOP

The Echange Server is the latest-- I beleive and will check-- it is hosted--

Is Exch 2007 SP1 a mandatory -- becausse this was working until just recently.