AntennaTracker problem (APM based)

This is about using APM 2.5 ,as AntennTracker: I did cut UART0 connection to telemetry port, and soldered pads to connect UART2 to Telemetry connector.

Telemetry radio is connected to telemetry port (Serial2), HW flow control disabled on radio, SERIAL2_BAUD = 57, SERIAL2_PROTOCOL = 2
GPS is connected to the usual port.
USB is connected to APM Planner 2

In MissionPlanner 2 , I see the MAVID of the Antenna tracker, but I miss any sign of the UAV (different MAVID) , AHI displayed belongs to AntennaTracker.

Antenna tracker does not turn toward the UAV, but is listed as D|Vector|stabilized, Active, Normal operation. APM Tracker lists is as disarmed, but the servos are holding.

The main issue here, is that I see no sign of the UAV.

wish I could delete this topic. HW flow control was not disabled on the radio.