[CentOS] 2 encrypted VG's on 1 disk - HOW?

I don't think it's a "distro related" issue, so i'm posting it here too:

http://unix.stackexchange.com/questions/11289/how-to-install-fedoraubuntu-with-encrypted-vgs-on-one-disk

what am i missing?

why doesn't GRUB offer the 2 distros at boot, why is it only offering only 1?? why doesn't it sees the other one??

Thanks for any help...