You'll need to set it as a Right Slave and then don't set any of the sub options in its config (they are high pass filters not low pass filters on any of the DSPs except the explicit subs), connect it to the centre / sub out, do slave comms to it and off you go!

The speaker has no idea about what it's actually connected to, so if it gets LFE on channel 2 of its input it will play it just as if it was channel 2 of left/right.

How well it works is another matter, of course... Your only adjustment will be in the processor config / calibration.

Best regards,
Julian