Basically, you need the passive bass bin connected in parallel with each satellite. As pointed out in the manual, you can accomplish this one of 3 ways:
1. Connect both the bass bin and its accompanying satellite to the AVR's speaker output.
2. Connect the bass bin to the AVR's speaker outputs then the satellite to the bass bin's inputs.
3. Connect the satellite to the AVR's speaker outputs then the bass bin to the satellite's inputs.
I would do whichever is both easiest and tidiest to wire.
Regarding using the AVR's "A" and "B" outputs, it should be OK despite the warning in the manual not to do so. But I would have to know more about your AVR's "A" and "B" outputs before I could say that with 100% surety. On most AVRs (and 2-channel receivers, too), nowadays, the "A" and "B" outputs simply represent parallel connections (as opposed to serial, as discussed in that old manual) off the front channel amplifiers.
Just be aware that connecting like that and operating the bass bin or satellite separately might present impedance issues. However, I didn't see (unless I missed it) a warning in the manual regarding operating them individually, so maybe there is something that is not so apparent about exactly how they operate. I seem to vaguely remember a discussion in the distant past either here or in another forum where someone wanted to either use the bass bins or the satellites separately and the upshot was that the impedance the satellite and bass bin presented individually was the same as when they were paralleled. How? Beats me. But if you DO connect this way, I would just make sure you always operate A+B together just to be safe.
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