RAK4631 + RAK19001 - UART1 configuration on RUI3 framework #6

Greetings! I am using the RAK4631 module on the RAK19001 WisBlock Dual IO Base Board with the RUI3 framework. I've been trying to use one of the available UART's interfaces to communicate with a M-BUS sensor. To do so, UART needs to be configured accordingly with the M-BUS requisites, meaning that I need to configure UART in order to have an Even Parity, otherwise I cannot communicate with the M-BUS sensor. For what I've seen the parity cannot be changed using the Serial1.begin() function (when using UART1), as it keeps a Non Parity configuration (the default SERIAL_8N1) although I have Serial1.begin(2400, SERIAL_8E1) on the setup. Is there any way to change the UART configurations on RUI3? Or it just can't be done?
I've tried to do the same using the arduino's framework and I was able to change the UART configuration and communicate with the M-BUS sensor, but I really wanted to use RUI3.
Hopefully I was clear explaining my issue.

Thanks in advance.