It took me long time to find this solution, enjoy it!!
1. convert mac .dmg file to iso which could be read in Linux or PC
download java app from
http://hem.bredband.net/catacombae/dmgx.html
you can put .jar file on linux or PC
> java -jar dmgXXXX.jar
This will pop-up simple GUi to choose your dmg file and name of ISO file.
2.mount iso file to your cdrom under linux
>mount -t hfsplus -o loop /directory/location_of_iso.iso /mnt/mountpoint
if you don't have mountpoint, just create it like dir
>mkdir mountpoint
under /mnt (ubuntu under /media)
Now you can read file from mounted dir, like cdrom, you can edit file and add/delete file before you burn it to cd/dvd
3. burn it to cd/dvd
use nero to brun iso file to cd/dvd.
all done.
