LoRaWAN time synch Lora E5 mini

I set one Rpi with wm1302 and TTN console, and one Lora E5 mini end device.
i manage to run and get uplink and downlink from the console
but when i try to set time Synchronization with AT command
i mannage just to time synch manualy with AT+RTC="year-month-day hour ", if i reset the Lora e5 device it come back to starting point 2000-01-01 00:xx:xx.
if i try to set direcly from the server with AT+LW=DTR i get +LW: DTR but no data.
my device is set with class C and Lora version 1.0.3.

someone can point me how to get this time synch data in the end device when it join to the LoRa network?

Did you had any luck?
I am trying the simplest solution just using ttn but have no response from command AT+LW=DTR
Was not suposed tho be already implemented?
Thanks