mqttClient-for-Legato with mosquitto setup?

I am trying to get mqttClient-for-Legato on a WP7700 / mangOH Red talking to a mosquitto server running on an Ubuntu host.

I have used mqtt config set to set the host IP in the config to 192.168.2.3 and port to 1883 (used by mosquitto), then enter mqtt session start, however it doesn’t seem to be attempting to connect. On the other hand I can connect using nc 192.168.2.3 1883 on the WP7700, mosquitto reports the new connection on the Ubuntu side.

Has anyone made this work?

It appears that the le_data routines do not work over the ECM interface with the host. Marked solved to close the question. Looks similar to this problem: