Please describe the problem:
Outlook (at least version 2003) does not display meeting requests scheduled from Evolution when the Evolution user has the "Secure MIME (S/MIME) -> Digitally sign outgoing messages (by default)" option checked in the Security tab of the Account Editor.  This is probably more of a stupid bug in Outlook than it is in Evolution Exchange, but for the sake of interoperability there should either be an option to not add digital signatures to meeting requests, or all meeting requests should be sent without digital signatures.  I prefer the former option to the latter since the latter behavior would be otherwise unexpected.

Steps to reproduce:
1. Enable "Secure MIME (S/MIME) -> Digitally sign outgoing messages (by default)" in the Security tab of the Account Editor.
2. Schedule a meeting with an Attendee who is using Outlook and let Evolution Exchange send a meeting request.



Actual results:
The Outlook user will be displayed an empty e-mail message without the expected accept/reject/etc. options on a normal meeting request.  The e-mail will appear blank but will have the proper Subject line.  No meeting details are displayed.  Outlook recognizes that there is a digital signature and displays the red ribbon icon on the message window.  Using "View->Options" to view the e-mail header information does show a text/calendar attachment, but it is completely inaccessible to the Outlook user.

Expected results:
The Outlook user would receive an e-mail which, when opened, would show the accept/reject/etc. icons at the top of the message window, allowing the meeting request to be added to his/her calendar as appropriate.

Does this happen every time?
Yes.

Other information: