Sodaq MQTT library: packet length greater than 128?

Hello, I am working on a Wireless Sensor Network, using Autonomo and GPRSBee Rev.6 (Sim800H). I am trying to send data using MQTT library (Sodaq MQTT) to a broker, but so far I can only send packets with a maximun lenght of 128 bytes. I set the MQTT_MAX_PACKET_LENGTH to 180 in the Sodaq_MQTT.h file but I do not know how to modify the cpp file to get it working.

The library only implements a 1 byte Remaining Length field. This limits it to a 7 bit value (128), as the 8th bit indicates a multi-byte Remaining Length field.

It wouldn’t be too difficult to modify it for a multi-byte Remaining Length field.

Details can be found here:
http://public.dhe.ibm.com/software/dw/webservices/ws-mqtt/mqtt-v3r1.html#msg-format