It did not work and the instructions in the manual were fairly complicated and involved delving into the Mac CLI, as the VBox GUI did not (and still does not) allow you to perform this setup. But I was disappointed when I tried to setup my existing Bootcamp Windows partition as a VirtualBox Virtual Machine. Since it was OpenSource (and free), I decided to give it a try. I started looking at VMWare Fusion and Parallels as a solution. This worked well for a few months until I got tired of having to reboot the Mac to run Windows via Bootcamp.
Since the Intel Mac allowed me to run Windows via Bootcamp, I was able to use this to run the Windows version of Quicken, since the Mac version of Quicken was not very good.
When I first got an Intel Mac in the summer of 2008, I decided that I could finally get rid of my Gateway PC running Windows ME. How to Use a MacOS Bootcamp Partition as a VirtualBox Guest Virtual Machine