ninihappy,
You seem to confuse some terms. Most likely, by the "EWF partition" you mean
Protected partition - the partition that is protected by EWF (storage volume
that is being masked by the EWF driver).
EWF volume is the EWF configuration volume - a storage partition of type
0x45 that is used by EWF and is not visible or recognized by the operating
system. It is comprised of the master EWF volume table, a number of overlay
stacks, and overlay data for all disk overlays.
Protected partion - this is what you are trying to protect.
You will also need some free (unpartitioned) space for EWF volume unless you
use Slobodan's approach with RAM based overlay (
www.xpefiles.com).
You should read on how EWF works and get familiar with its architecture:
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/xpehelp/html/startpage.asp.
KM