Regen on Kelly KBS - how to regen after stop?

I use a kelly KBS36051 Controller in two applications that require permanent regen. While doing so I encounter bigger problems for which i have no solution. The controller is attached to a 36V battery pack and a sensored brushless motor in fixed gear to the wheel/crank (no freewheel). I use a throttle thumb regulator and a brake switch.

• One application is riding down a hill. Regen is used to brake almost to stop. After the stop no throttle is used to get rolling again. This procedure is repeated multiple times.
• The other application is using a kelly controller attached to a brushless motor on a crank. A human pedals in order to recharge the accumulator.

In this two applications i do encounter a special problem:
The motor is turning and throttle is released. I activate the regen/brake switch and regen starts slowing the motor and vehicle. After the motor rpm speed falls under a certain rpm, Regen suddenly stops and freewheeling starts, although the brake switch is active. If speeds increase again (only rolling or only pedaling), regen stays disabled, no matter what state the brake switch is in. Regen does not engage again. It only works again if throttle is used, released and the brake switch is activated again.
I already looked through the manual, this forum and the kelly controller software. Nowhere i did find a solution, how to activate Regen after a stop without applying throttle between the 2 Regen phases. Does anyone know help?
Thank you for sharing your thoughts,
lloudspeaker