osx - Run Windows in VirtualBox from Mac with rEFIt

I have a MacBook with OS X Lion, installed Windows 7 via Boot Camp, added Linux (Backtrack) using rEFIt.

I now access OS X, Windows and BackTrack via rEFIt's boot menu. When I choose Backtrack or Windows I am routed to GRUB boot loader, Windows 7 being one of GRUB's options. If I choose Windows, it boots Windows properly.

Output of fdisk /dev/disk0:

Disk: /dev/disk0    geometry: 60801/255/63 [976773168 sectors]  
Signature: 0xAA55  
Starting Ending  
id  cyl  hd sec -  cyl  hd sec [     start -       size]  
 1: EE 1023 254  63 - 1023 254  63 [         1 -     409639] <Unknown ID>  
 2: AF 1023 254  63 - 1023 254  63 [    409640 -  741694744] HFS+          
*3: 07 1023 254  63 - 1023 254  63 [ 819032064 -  157741056] HPFS/QNX/AUX  
 4: 82 1023 254  63 - 1023 254  63 [ 742105088 -    1951744] Linux swap    

Output of diskutil list:

/dev/disk0  
   #:                       TYPE NAME                    SIZE       IDENTIFIER  
   0:      GUID_partition_scheme                        *500.1 GB   disk0  
   1:                        EFI                         209.7 MB   disk0s1  
   2:                  Apple_HFS Macintosh HD            379.7 GB   disk0s2  
   3:       Microsoft Basic Data BOOTCAMP                80.8 GB    disk0s3  
   4:                 Linux Swap                         999.3 MB   disk0s4  
   5:       Microsoft Basic Data                         38.4 GB    disk0s5  

I installed VirtualBox, created a virtual machine with the existing Backtrack install by doing the following:

• Click "new" in VirtualBox
• Input name and click Continue
• Choose RAM size and click Continue
• Change Backtrack partition permissions to 777
• sudo VBoxManage internalcommands createrawvmdk -filename backtrack* -rawdisk /dev/disk0s5
• sudo chown <username> backtrack*
• Select "use existing file" in VirtualBox, select backtrack.vmdk and click Continue
• Finish

The Backtrack VM works.

I tried the same for Windows 7, using partition number 3 and 5 (for the vboxmanage command above). Does not work. The VM is created but I can't start it. When creating the VM with partition 3 it just hangs when I launch it.