[Plugin: All-in-One Event Calendar] Custom Post Templates not working

I have followed the common instructions for custom post templates so that I could define my own widget.

How to define a custom template for single event view?:
1. Create a new template in your theme folder.
2. Name it single-ai1ec_event.php
3. Copy the contents of single.php to single-ai1ec_event.php
4. Edit single-ai1ec_event.php anyway you like.
5. Navigate to any event to see your changes

It is probably something about how my theme functions. But, I thought that I could make the change in the plugin file so that is would use the template I created using the directions above. I gave the template a custom name so that I could apply the template.

I have 100’s of events, so I cannot manually change each of them!

http://wordpress.org/extend/plugins/all-in-one-event-calendar/