Unlike the Ping it uses serial data input and output with auto baud detection.
You could try it two ways:
1. Either add the hardware as shown in the WebbotLib for the Dynamixel AX12 servos. This uses a UART tx/rx pins plus a direction pin that connects only one of them at a time to the single serial pin on the device.
2. Or you could try using a software UART and then use the same pin in the MAKE command for both the Tx and Rx pin.