After some testing and user frustration, it appears that v.6.7.2 does not properly encrypt/decrypt attachments when using Outlook 2007 Calendar invitations (.ics files) and secure delivery push (SWD).
I have tested and the recipient receives the meeting info in a text format (see below) but any attachment appears to be stripped from the message:
When: Tuesday, March 08, 2011 5:30 PM-6:00 PM (UTC-06:00) Central Time (US & Canada).
Note: The GMT offset above does not reflect daylight saving time adjustments.
Is there any workaround to this behavior? Apparently our users were actively doing this with the 6.1.2 push implementation that we migrated from.