Thank you for your post. Attachments can currently not be exported. However, we have a feature request in the backlog to allow export data including attachments. I will create a support case for you and link your new case to this open request in order for you to be contacted when there is an update.
I had submitted an email asking about this as well. It seems the attachments are rather elusive otherwise, so this feature would be very beneficial for anyone who needs to verify / audit testing results. If others add their names to the request it will hopefully be bumped up in the list and expedited.