Hello Robbie,
Thanks for the information. At this time, you are not able to add attachments to the calendar events. This would be a feature requests for the application.
Are you trying to bring over events using ActiveSync or IMAP connections ? You may want to try to use the IMAP account first and then move over the details. Once you make the connection to ActiveSync it will look for the account details within the SmarterMail calendar and not from Outlook.
Thanks.