Your Integra receiver has a jack on the back panel that is labeled "SUBWOOFER PRE OUT". That's the jack that you want to use on the receiver.
The Velodyne subwoofer has line-level connections (the ones with RCA jacks), and those are what you should use. The owner's manual for that sub is available at
this link if you don't have one (just pay special attention to the page numbers at the bottom - they are not in order). It explains how to set the unit up. In particular, I recommend that you use the bass management in the Integra and bypass the crossover in the sub. To bypass the sub's crossover, set the "SUBWOOFER DIRECT/INTERNAL X-OVER" switch to "SUBWOOFER DIRECT". I'm not sure if you need to connect the subwoofer output from the receiver to both the left and right line-level inputs on the sub or not. You can always get a y-splitter to do that.
That's how I recommend connecting it. If you have any questions about setting it up, just let us know.
EDIT: Ahhh, I see that Midcow was quicker on the draw!