1st, I know the signal-out leads from the pins of PL and
DIN-AUX are mirrored or in an opposite way.
2nd, the drawing I was refering to, the one Beobird posted
and made by you, says the PL-out goes to the sub. (Which is the right thing to
do)
What is confusing me is that you say it has to be connected
through AUX, which is not right. Because:
3rd, the A.AUX (not the PL) of a BS9000 is a fixed signal. Volume
of the BS9000 is not relevant. If you connect these leads to any sub, the
volume is not controllable, thus very loud in this case.
To resume, the A.AUX cannot be used. The sub has to be
controlled through PL.