I think your second question is going in the right direction. If your main reason for getting an ICBM is SACD and DVD-Audio (the formats that the ICBM was developed for), you could simply locate the ICBM between your universal player's six channel analog output and your receiver. Once you've done that, set the player's speaker settings to "large" and sub to "on". This way, Dolby Digital and DTS will be processed by the receiver and the receiver's bass management (with a fixed 80Hz crossover), while the ICBM handles bass management for high resolution audio.

The comment about the subwoofer crossover setting applies also to using the bass management in your receiver with Dolby Digital and DTS - in fact, it could also be effective to disable the crossover in your subwoofer. The idea is to handle all bass management at one point (the ICBM or the receiver), not performing bass management multiple times.