A bit late, but I think this could be of interest for many Users.
If you are trying to boot raw dd, EWF or AFF images in VB, you may use my GPL'ed program entitled xmount (https://www.pinguin.lu
It allows you to convert on-the-fly between the above formats and a VDI or VMDK file. All changes to the virtual file are written to a separate cache file in order to not modify the original image file.
Prebuild packages of xmount for any Debian based Linux are provided and no, it won't run under Windows
And if you plan to boot a Micro$oft os, you should probably have a look at my other project entitled OpenGates that will patch Windows in order to boot in your virtual machine.