RAK7289 MQTT Keepalive configuration not working

Hi, I’m trying to configure RAK7289 gateway with a external MQTT broker using a satellite link.
The gateway is working without problems with our MQTT Broker using internet office link, with keepalive setting to 10 sec.
We change the setting to 60 sec in order to work with a satellite link, but it never change after save, reinit o reboot the gateway. It is showed with a traffic analizer on MQTT Broker side.
Besides, the same happen with QoS Configuration, never get the changes.
Somebody experienced this behavior?
Can we access to OpenWRT by ssh and change configuration file for MQTT in some way, not using LuCi?
Thank you in advance for any suggestion or opinion