Shortcode [events_list_grouped] sort by date desc

I would like to sort the past events by start date descending group by year (also descending). I have tried

[events_list_grouped mode=”yearly” scope=”past” orderby=”event_start_date” order=”desc”]
event list here…
[/events_list_grouped]

but it appears it is sorting the group descending (e.g. 2013, 2012), but the events inside is not sorted with the latest first.

Ben

http://wordpress.org/plugins/events-manager/