Stand alone, you can't use the MIDI Jacks on the back of the RM/RML to control the functions of the mixer. UC Surface does not support remote MIDI Mapping.
However, you can do this by using Studio One, when Studio One launches, it takes control of the Mixer (like our Studio 192 series). Map your controller through the DAW to control the pre-amp gain, fader levels, mute, pan, solo. Create mixes and map the mixes to your MIDI Controller. You basically use Studio One in place of your UC Surface software.
You'll need to make sure your RM / RML mixer is connected via 1394 to your system to make this work.