I've got the tone in its own track, but I can't find/setup a plugin that will open for a moment when the kick kicks, and then close again when the kick ain't kickin'.  A sidechain-able gate?  Like what?  Or do I already have what I need, but am too dumb to figure it out on my own.  Likely the latter.
 
55 Hz is root tone of key of A. 
 
PS: I did a search for 'gate' on this forum but came up empty.

sonoitus (spelling?) Gate should work and is included in Sonar.  Really any gate with a side chain should work.

Sonitus (sp) is the first thing I worked with, to no avail.  There is no TRUE sidechain option.  By "true" I mean opening the sine wave tone on Track 33 using the Kick drum audio on track 8.  The Help says the following but what I think this means is that they are suggesting using EQ on the track to make it open and close properly.  That is not side-chaining, methinks. 
 
Quote from Help:
 
Because of limitations in both the DirectX and VST plug-in architectures, it is
not possible to create audio or control signal busses between plug-ins in any
standard way. This limitation makes it difficult to implement a standard gate
sidechain input that can accept an "external" trigger signal. It is possible to
create a "hack" that allows signals to flow between our own plug-ins, but we
feel that it just is not the proper way to do things. The sidechain
functionality in the fx:gate plug-in allows you to use high- and lowpass filters
on the incoming audio to create a "sidechain trigger signal".

The only Side chainable gate I've got is the PC4 Exp/Gate which I think is a paid purchase.
 
According to the version comparison chart, there is a gate known as the Gate Expander GX622.
 
This appears to be part of the Nomad Factory suite but I don't have it, at least not on my laptop installation, so I can't say whether it's S/C or not

The Sonitus Gate does have a sidechain and it works in SONAR Platinum. If I wanted to setup a tone generator to be triggered by a kick drum.
 
Add the Gate in the FX bin after the tone generator (in my case MOscillator) on an audio track
Add a send to the Gate from  the Kick track
Adjust the Gate parameters to suit starting with the threshold to open the gate.

OK, that works.  Thanks.
 
 

Hi i'm glad that you solved but for curiosity check this plugin by Boz Digital.
Dave Pensado use this useful tool.
best

http://www.bozdigitallabs.com/product/little-foot/

make the tone into a sample and trim it, copy the kick track and use drum replacer or drumagog to sample it. mix it in with the kick track. just a thought

Or extract the MIDI and use it to drive a synth.

Isn't this application exactly what DR was designed for?  If you create a sample from your tone shaped the way you want it, DR could trigger that sample for you.
 
You can also use DR to extract the MIDI for use as scook suggests.