I think trial-and-error is the name of the game.
One experiment is setting the BP7002 to small, Crossover @ 80Hz.
Get 2 Y-cable. The 1Male-2Female type like this:
http://www.amazon.com/Raptor-NBRCA-Y2-0-5-Feet-Female-Adaptor/dp/B0002EXFCY/ref=sr_1_1?s=automotive&ie=UTF8&qid=1310447106&sr=1-1
Now your single Sub output becomes three: connect one Y-cable to your AVR sub output, then connect the second Y-cable to the firt Y-cable.
Then connect 3 cabes to the subs: SC1, and both BP7002s LFE inputs.
Start by setting all 3 subs to 50% volume (12 o'clock) on back of each sub/BP7002.
On the AVR now level match all channels manually using a digital SPL meter to 75dB-C weight, slow response.
If you don't have a SPL meter, then just run automatic calibration. But afterwards, turn off the EQ completely. The calibration will set the channel levels for you. But you have to manually set the speakers to small and crossover to 80Hz manually.