Mckaskie,
Sadly, I had the same issue with an XP machine. I tried various driver configurations as well to see if I could get it work and still nothing. Please know that I am not saying it won't work, I just haven't been able to find the answer yet.
However, as soon as I went through the installation process on an old Windows 7 machine everything went perfectly with CGMiner.
I followed the instructions from this post:
https://bitcointalk.org/index.php?topic=220450.msg2321308#msg2321308. The bottom half of the instructions is what I used where it explains using version 3.4.2.
The trick that I found was to install the drivers with the BE's installed. With a second Windows 7 machine, I went through the same process of installing the drivers with the BE's installed and didn't even restart the machine, just simply started CGMiner and it picked up all 5 without question.
I know this doesn't' help with your XP machine, but if it worked that easily on a Windows 7, then there has to be a way to make it work on XP. I'll have more time this weekend, so I find anything else, I'll come back and post it here.