Not all programs can just be added into PE..
As there may be certain files dependencies' or registry entries also needed...
The best thing for them to try is running the ghost installer from within the PE environment...
If it works, they would have to record the changes into a mounted PE image and capture into new image.
Modify PE - mounts the current boot.wim
you add your program(s) into the mounted PE directory and then Modify PE will capture and unmount that directory into a new boot.wim, then just swap-out the boot.wim that Modify SE created with the one in boot media / sources folder