How to ISO-boot from an hfs partition in an apple with dual boot?

How to ISO-boot from an hfs partition in an apple with dual boot?

I can easily boot debian based (and some other) live linux systems from
their ISO-image file with grub2 in an Apple machine with dual boot. Using
the same menuentry scheme but pointing to a file in an HFS+ partition is
not working. When I edit the menuentry in grub's menu during boot time. I
add a line set root=(hd0,2) and using the tab key for auto-completion I
can see that grub2 reads the partition filesystem ok. Even when it starts
to boot, the process continues a while and then stops with a message that
the file (the isofile) cannot be found.
I would like to know if someone has done it or if it is still not possible.