Uavcan px4 used as replacement of a babel

Hello, px4 as a replacement of the zubax babel is not working as intended.
It connects ok with the UAVCAN GUI tool but then nothing happens.

The UAVCAN_ENABLE parameter is set to 3.

We digged a little in the code and it appears that the firmware server is not started because some function deep inside the uavcan library code are not populated, those functions appears to be virtual