Pixhawk SBUS output

I’m trying to read SBUS output value on an arduino board, but All read channels values are fixed and null, expected the channel 3 : 363.

My SBUS reader librairie works with a SBUS RC receiver, and I use an sbus inverter between Pixhawk and Arduino

The documentation suggests that SBUS output is not yet implemented, and the SBUS port is an input. http://ardupilot.org/plane/docs/common-pixhawk-overview.html#common-pixhawk-overview

Does that help?