oscdimg -b[location of OEM tool kit WINPE files]\etfsboot.com -n [location of your Image] [iso file]
i.e.
oscdimg -bd:\build_x86\etfsboot.com -n c:\pebuilder3110a\bartpe d:\bartpe.iso

I created a CMD file to allow me to create an ISO of the BARTPE image after removing the NuMenu as I wanted to be able to have the shell loaded but with no menu. Bart Errors out due to the menu.xml files if the menu is not loaded.. so this quickly allows the image to be created.

OSCDIMG is available in the OEM toolkit.