Changing baud rate of a DHRIO module

Hi

I am trying to increase the baud rate of a 1756 DHRIO series B module from 57.6kbps to 230 kbps. You can not do it through switch settings or using RsLinx (even Gateway version). From the local AB tech support, I learnt that we can change the baud by setting the channel selection switch to 2 for both the channel A and B. But this does not work (when configuring a DHRIO in RsLogix 5K, press help and this procedure is listed). Has anyone done what I am trying to do?
I know that series C comes with default 230 kbps.

To change series B to series C, flash the series C firmware to the series B DHRIO module. Setting the BAUD rate switch on Channel A to 3
will allow 230Kbps.