Not sure if this works with the CD images, I only tried this with the generic ones and mounted them as an HDD then.
I edited the generic image, 'generic-pc-1.33.img' and the sys admins exported it as an .iso/.img that was then mounted as a "CD" in the virtual CDROM via VCenter.
I currently have the modified .img in /root of the server I wish to use as M0n0wall. Should I mount it as a filesystem using 'mount' and set the 'boot0' boot manager to boot from that filesystem? The install guides assume I have the .img on external media, which I why I originally attempted to install as a virtual CD ROM.
Thanks for the help thus far.