There are discussions here about the missing bcc in Outlook 2013.

http://www.slipstick.com/outlook/ema...sent-messages/
From above: "Note: When you use Gmail IMAP accounts and save the sent items on the Gmail server, you won’t see the BCC names on sent items. You need to save sent items locally if you want to see the BCC names. Other IMAP servers may behave the same way, but in the servers I have access to, only Gmail doesn’t show the BCC addresses."

http://answers.microsoft.com/en-us/o...6-eaa4fb0cee33
A possibly better than nothing workaround from above: "... open the message and click on the small arrow below "Follow up" this displays the BCC recipients ..."

The End.