programs: nLite, cdimage (Microsoft), cdimage gui (beta3 by Cyberian)

1. extract the image contents with IsoBuster, UltraISO or equivalent
2. extract CD Boot Sector with IsoBuster
3. use nLite to perform changes and shrinks
4. copy i386/txtsetup.sif to the boot dirrectory CD:/ of the windows version you have tweaked
5. edit txtsetup.sif and find field
   [setup data] setupsourcepath= “\”
   replacing \ with the actual path on the multiboot CD (i.e. the folder containing the i386 folder of the windows flavor)
6. use cdimage with the following options
   -tMM/DD/YYYY,HH:MM:DD -g -h -n -b [bootsector file] -x -o -m
   cdimage is a really handy tool capable to prevent multiple identical files to be stored on the CDROM through the creation of kind of symlinks.
7. test the cd with an emulator like vmware.
8. note: if things go wrong remember to check in a hexeditor each setupldr.bin file of each windows flavor. This file should have all occourences stating i386/ replaced to the actual path of the windows flavour.