Send dimmer value&channel to serial port


I have an arduino attached to my RPi2.
The Arduino Leonardo controls an 8-channel AC dimmer.

The arduino accepts commands of the following form:
|channel| |dimm value|
where channel is 0-7 and dimm value is 0 (brightest) - 500 (darkest).
I am using serial port /dev/ttyACM0.

Could you please help my find the right binding configuration for the openhab serial binding?
(I want to use this binding: