How to determine if message will be encrypted on Send

[sf0]

I'm trying to remove certain UserProperties when messages are sent. Al
is well unless Outlook cancels the Send event when it has problem
encrypting (see Outlook's message further below). In that case, th
user has 2 options: "Send Unencrypted" or "Cancel". My problem is
cannot determine which option the user selected.

The significance of these options is as follows: if the user select
"Cancel", the UserProperties which were removed in MailItem_Send mus
be restored (I have a solution for this in the Activate event); if th
user selects "Send Unencrypted", I don't want to do anything.

The only indication I have that the user has opted to "Sen
Unencrypted" is the 2003 Word editor throws an error when I attempt t
access the currentItem.UserProperties. No error is thrown in 200
default editor or 2007.

Is there a way to determine which button the user clicked?
Alternatively, is there a way to determine if Outlook intends t
encrypt the message or not? Or should I remove these UserPropertie
somewhere other than MailItem_Send?

FYI, I don't have access to Redemption or any other 3rd part
software.

Outlook's message:
Microsoft Outlook had problems encrypting this message because th
following recipients had missing or invalid certificates, o
conflicting or
unsupported encryption capabilities...

Thank you in advance for your help

 

[sf0]

Alternatively, is there a way to validate the certificates of the sender
and recipients? If so, I could cancel the MailItem_Send event and not
have to worry about restoring my currentItem to it's pre-send State.