This is a simple circuit I came up with for a les paul style guitar with two tbx's and a coil split on each of the volumes. The tbx controls were based off of Docs mod for better use in a passive guitar. The one thing I was having trouble with was how to connect the TBXs to the volume and pickup selector. All the diagrams say for the middle lug in the 250k pot to got to the selector switch and for the middle lug in the 1meg to go to volume, but never where exactly to. I also suspect some grounding issues.
Sorry, I can't get the image to load on here, so check the attachment.
TBX Wiring Template.pdf
The middle lug on the 1M can go to the volume where the pickup it will control is connected (lug 3 as looking at the pot with the shaft pointing at you).

The "doc's mod" diagrams don't have the middle lug of the 250k side connected to anything else. So your diagram should be right when you connect lug 2 of the 1M side to lug 3 (the one that isn't grounded) of the volume pot.
One thing I did notice however with the docs mod is that it appears to still not be cutting any bass. At least the way I see it, doesn't the 220 kΩ resistor still just act as a shunt and not a bass cut?
Edit: So there is no problem with the attached wiring?
The attached wiring needs to have lug 2 of the 1M side to lug 3 of the volume pot, then it will be correct.

I don't think this one is supposed to cut bass, per se, but rather it imitates a "no-load" condition beyond the center detent in the pot (giving the illusion of "cutting" bass by having more treble present). Getting it to do a legit bass-cut would require a small-value cap on the 1M side.

Here's the original thread where the Doc's Mod came up: http://www.fenderforum.com/forum.html?db=&topic_number=194509&offset=0
And here's the original document of the mod from Blue Guitar (PDF file): http://www.blueguitar.org/new/schem/_gtr/tbx-mods_and_details.pdf