Hi Dan, 

To add to what everyone else has suggested, the option to exporty users from the user list as a domain admin was not available in 14.x.  However, you can look at a reports to get a list of users and export that to a .csv.  As the system administrator you can use the Disk Usage report in System Summary Reports > Traffic Reports.  Click on the domain and it should drill down to the users on that domain.  You should then be able to export the report to a .csv and get rid of any information the customer does not need.  

Another option is to take a screenshot of the list of users, use MicroSoft OneNote (or another similar product) to insert your image, you should then be able to copy the text from the image and past that in the same note.  Be cautous with this though, as the formatting can sometimes be a bit screwy and OneNote does not always see the text correctly (an l may be copied as 1, etc.).