It didnt' actually elude them, but AFAIK it's not yet implemented in stuff from ES:Toorbough ULL-Zeveigh said:that backpedal regen is fn brilliant.
its so bloody obvious that as usual it eluded all the ES geniuses, slapping my forehead.
I've seen backpedal regen come up in the CA3 beta thread at some point as a feature request, if not an actual way to make it do that.
It's even listed on this page
http://www.ebikes.ca/product-info/cycle-analyst-3.html#features-requests-and-bug-reports
Enable backwards pedaling regen control In quadrature PAS mode, enable an option that backwards pedaling triggers the 0-0.8V proportional throttle regen
EDIT: using just one possible search (pedal backwards regen) I found some references for it, starting as long ago as April 2012. There's probably others with other terms that don't come up in this search:
https://endless-sphere.com/forums/viewtopic.php?f=4&t=37964&p=570265&hilit=pedal+backwards+regen#p570265
https://endless-sphere.com/forums/viewtopic.php?f=31&t=65031&p=1116000&hilit=pedal+backwards+regen#p1116000
https://endless-sphere.com/forums/viewtopic.php?f=31&t=65031&p=1123997&hilit=pedal+backwards+regen#p1123997
https://endless-sphere.com/forums/viewtopic.php?f=4&t=37964&p=1245232&hilit=pedal+backwards+regen#p1245232
https://endless-sphere.com/forums/viewtopic.php?f=4&t=37964&p=1254203&hilit=pedal+backwards+regen#p1254203
And apparently at least at one time the Copenhagen wheel did this
https://endless-sphere.com/forums/viewtopic.php?f=3&t=14717&p=1088256&hilit=pedal+backwards+regen#p1088256
This post proposes the basic idea back in May 2015:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=69143&p=1042750&hilit=pedal+backwards+regen#p1042750