We need to determine where the ICBM goes in the signal path first.

If you have a universal DVD player (DVD-Audio and SACD), you would put the ICBM between the player's six-channel analog output and the receiver's six-channel analog input. Since receivers generally don't apply any bass management to that input, your receiver's bass management settings don't apply and the ICBM takes care of it. This is the scenario for which the ICBM was designed.

If you want the ICBM do handle all bass management duties, it would need to be after your receiver but before your amp - which means you would either need to have a separate amp or a receiver with pre-out/main-in jumpers to let you tuck the ICBM between the receiver's pre-amp section and its amps. Assuming that is possible in your case, you would want to set all speakers to large in the receiver (thereby avoiding all crossovers at the receiver) and letting the ICBM handle the bass management by itself.