Connecting Passive Subwoofer to Amp - Newbie Questions

I need some help connecting a passive subwoofer with my primary rec/amp and the rec/amp I'll like to use to power the sub. Below are my particulars.

- My primary rec/amp is a Yamaha RX-V2700 which has a subwoofer pre out jack (it appears to be a RCA-style plug).

- My sub is a MTX HTS28W in-wall unit. I'm pretty sure it has binding posts for the speaker input.

- I plan to use an old Pioneer 4 X 110 watt (VSX-5400) as the amp for the sub. Herein lies what I believe to be my major dilemma. I think I need to use the dual (R/L) "Front Power Amp In jacks" on the Pioneer sub amp. The manual says that I remove the "connector bars" from these input jacks when in use but that I won't get sound from the front speaks when these inputs are in use??? Is this the correct input from the primary amp? If so, what is my output to the speakers?

Here are my other questions, although the initial hook-up question above may make some of these questions moot:

1. From the primary amp, I'll be going from a single RCA-style plug to a dual plugs on the sub amp. So, can I just use an RCA-style splitter?
2. From the sub amp, will I run speaker wire from the front, main R/L speakers out to the subwoofer?
3. Will the volume be controlled by the primary or sub amp (or both).

Am I being an idiot for doing it this way??? Am I missing something??? I think I understand general audio setups pretty well but the passive subwoofer connection is really throwing me for a loop.

Any help would be greatly appreciated!

tbs

btw - I tried to post this somewhere else but haven't gotten any replies. I just wanted to make you all aware of this so I don't get slammed for cross-posting. Thanks.