Boot raw OS X 10.6 in Windows 7 on Mac hardware?

[Particle Man]

I have an early 2008 MacBook Pro with OS X 10.6 (Snow Leopard) and Windows 7 Pro x64 installed on separate partitions, plus another partition between them. I use the boot manager rEFIt.

I would like to boot OS X in VirtualBox when in Windows 7, so I created a VMDK with "full hard disk" access.

With VirtualBox 4.2.x, I get this error at boot, probably the same as mentioned in the locked thread /viewtopic.php?f=22&t=51657:

Fsw ERROR: InstallMultipleProtocolInterfaces returned 20000008

And it boots into status mode and stalls at "AppleIntelCPUPowerManagementClient: ready"

Downgrading to 4.1.22, it boots into the EFI console.