Custom namespace for uXRCE client in PX4

I require to use a custom namespace, and I managed to do it through the extras.txt file, as suggested in this post:

During SITL, it is easy to just set up the environmental variable PX4_UXRCE_DDS_NS, but not the case in real-world devices like Pixhawk. Any particular reason why it has not been yet included maybe as a parameter, just like the IP (UXRCE_DDS_AG_IP)?