I have successfully communicated with my BlueESCs over the I2C signal control line.
Each BlueESC is delivered with the default 0x29 hex address.
You can load the Arduino I2C code, found in the BlueESC Documentation, onto an Arduino Uno to communicate with the ESC at the default address. You can even use the send function in the Arduino IDE Serial Terminal to change the motor speeds from forward to reverse over the ESCs speed range. Make sure you include the Blue Robotics Arduino_I2C_ESC library into the Arduino IDE library before using the program.
Since I have 6 BlueESCs I had to give each ESC a unique hex address. I started with 0x29 and ended with 0x2e.
I loaded the ESC firmware files (BlueESC Firmware (2015-07-09 a34f109)) for each unique hex address onto my PC and used the ArduinoUSBLinker on the Arduino Uno and the KKMulticopterTool on my PC to load each ESC with its own unique hex address.
I had no problem changing the hex address of each ESC from 0x29 to a unique, new hex address.
You can also read about my BlueESC programming efforts here.
Hope this helps.