Controlling ESC with Arduino and Simulink

Hello,

I'm developing a hexacopter controller, but I cannot start the motors. I am using a RadioLink R9DS receiver, SN40A ESCs with BLHeli 14.9 firmware, connected to the PWM ports of an Arduino Mega 2560. I'm using Simulink's RCReceive Block for signal reception, which works normally (see through display and scope) However connecting the PWM outputs, the motor does not turn on. I know that both work, because if you connect the ESC to the RC, the motor works. Does anyone know what's missing or what I'm doing wrong?