"Aural Ecstasy"???
(must.... bite.... tongue...
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)
Not all subs have outputs on them. Apparently this is one of them.
From what I can see, I'd say your best bet is to take your speaker level output from the receiver and feed it to one (or maybe jumpered to both) of the speaker level inputs on the subwoofer.
You're either gonna have to live with the bass management on your receiver of face the fact that the speakers will be running full range, which is not necessarily a bad thing if they fade off the low end gracefully.