Hello Catharine,
To create the unfolded plate detail, you should use a different process than what you used before.
From the "User Drawing" Toolbar the 5th icon from left or from top, the last option is called: Single Part beam Development, you can use it to create the unfolded view of your plate. If you call us at support, we can also explain you how can be possible to create your own process typically for those conditions.
Regards,