Boot from iso

Hi, I love the ability in the beta to boot from iso .... however I'm not sure it is fully working yet.

I have two iso files, Norton Ghost and WIndows7 Ultimate x64 install.

I can succesfully boot the Norton Ghost but when I try to boot Windws 7 setup disk it drops straight out to grub.

Any ideas please ?
Oops, I should have said ... the ram based one, correctly loads the DVD into memory, but then Windows obviously fails because it does not have enough memory to load i'ts own ramdisk.

The disk based is of more concern. This is the one that just drops straight into grub.
Thanks - a bit more information for you ... it seems that I can successfully boot the Windows 7 x86 iso ... so the problem only seems to be when I try to boot the Windows 7 x64 iso .... a 64 bit issue ???