www.usblyzer.com
I've used this before. You can get a 30 day trial, and it is very effective.
Be aware that isochronous data is displayed to the byte count received, but from the overall buffer - so it does not show all the incoming data.

http://www.wingmanteam.com/usbsnoopy/
open source, similar functionality. Writes a log file from kernel mode...
The logs can get very large, and start from the time you plug in the device.

All the available Behringer drivers are available here:
http://emd.republika.pl/

Google for Cypress Suite USB 3.4.7
The BCA-2000 8051 firmware is derived from the sample source provided by Cypress.

For basic examination of the firmware, D52 does a reasonable job
http://www.bipom.com/dis51.php
See BCA2000-2106-firmwarebin.ctl if you want to disassemble the firmware to further understand the command interpretation.
In theory, it would not be too difficult to re-create the original Behringer source, but be aware of possible licensing implications.

Google for
CY7C68013.pdf
CS8406_F6.pdf
CS8416_F3.pdf
ak4626vq_bab2816d8c.pdf

to build the BCA-2000 driver, you will need the ASIO SDK from Steinberg
http://www.steinberg.net/en/company/developer.html

to build the BCA-2000 driver, you will need the libusbk source
http://sourceforge.net/projects/libusbk/files/libusbK-release/3.0.6.0/

I have had very little luck with VMWare on my Windows 7 64 bit - i.e. the original Behringer driver does not work well in XP in a VM on my laptop.
In order to analyse the BCA-2000, i had to create a 'real' XP machine, then the driver worked fine, even with either of the two loggers in chain.