I usually make the flight plans using auto function , and export them , then i load them into little navmaps , but starting of descent point is diferent in both programs (p2atc and little navmaps), how can i export the flightplam with the descent pint information ?

thanks

The descent point is going to be calculated by your FMS or GPS.  It is therefore not exported as it would cause an error if you tried loading it.

You can modify planned Groundspeed and descent rate in P2A to get the TOD to be about the same as in the aircraft.

Dave