Apple's Boot Camp specifically supports Windows XP SP2 and Windows Vista and unfortunately not Linux. Running Linux is a hack, albeit a very respectable one! (You could seemingly substitute "Linux" in your question for hundreds (if not thousands) of other x86 OS's some of which Apple built in the past like NeXTStep!)
OK argument aside, from what I've read here the Boot Camp scanner detects a Windows partition that has a copy of boot.ini. That won't ordinarily be on a Linux partition that sort of answers the 'why'. The 'how to make it work' is to build a "Boot Camp VM" and a virtual disk with a raw partition specification. The raw partition disk utility is under /Library/Application Support/VMware Fusion/vmware-rawdiskCreator. If you need a copy of the VM configuration (vmx) file I can add that as an attachment from my normal Boot Camp VM.
url=http://fearandloath.us/vmware-fusion-bootcamp-partition.htmlHere[/url] and url=http://taylorbanks.com/blog/ubuntu-on-the-macbook-pro-physical-virtual-or-both/here[/url] are two links about creating raw-disk-based Linux VMs.
(With a little tweaking, you can even improve it, creating a VM with the name Ubuntu, exactly as if it were created from within the Fusion GUI: just delete the virtual hard drive in the first step and then choose Ubuntu as the name for the raw disk in the third step (at least, IIRC: it was some time ago...).)
I did it some months ago with Ubuntu 8.04, and everything worked well, except for some little glitch with the VMware Tools: IIRC, between every native and VM reboot, a new xorg.conf file was created (thus accumulating them in /etc/X11), so it didn't quite remember everything (as instead happens in a "real" Windows Boot Camp VM) and the keyboard layout was reset to US English; sorry, I don't remember the actual details anymore, but the essence is that the Tools integration wasn't 100% seamless between "native" and "virtual machine" reboots.
Maybe that is already solved or could be improved upon...?
Anyway, raw disk VM creation and management from within the Fusion GUI would be great thing!
FWIW, I used the fearandloath.us link to create an Ubuntu VM. I got it to work fine without any great issue. If you managed to install Ubuntu on its own partition, you should be able to follow the instructions and get it booting in Ubuntu.
Oh. I installed Ubuntu on an extFS partition. This means that I'm using ExtFSManager on the Mac side to see the extFS partition http://sourceforge.net/projects/ext2fsx/.
The Mac OS X Ext2 Filesystem, while working also for me on both Tiger and Leopard (but read-only for Ext3 volumes) and with a very handy preference pane, sadly seems to have become an unmaintained project for more than two years, now.
FYI, there is also a MacFUSE plugin - based on url=http://sourceforge.net/projects/ext2fuseext2fuse[/url] - being worked on, as can be seen from url=http://groups.google.com/group/macfuse/browse_thread/thread/be92e719459824bc/0c7af937d4d4e6de?lnk=gst&q=ext2#0c7af937d4d4e6dehere[/url], on their forum; the author of the Mac OS X package is the same who maintains the Mac OS X NTFS-3G package (and also HFSExplorer, etc.), so it should hopefully become something promising and a little more usable, sooner or later.
Thus, eventually we could, for example, even be able to mount Linux VMware disk images in the Finder...
I'm trying to do a simmilar thing.
I have my drive split into 5 partitions.
MacOS X 10.6 | windows 7 (32gb) | Ubuntu | BT4 | MacOS X 10.6 (Test Enviroment 32gb)
I can boot into any partition i want by holding down the "option" key and it works great but once in OS X i'd like to be able to load the partitions as a VM like I can do with the bootcamp partition. I've looked into this raw disk creater utility but can't get it to read my disk and don't know what I'm doing wrong. below is what a few of my command line options were.
<USER>/Library/Application Support/VMware Fusion $ ./vmware-rawdiskCreator create /dev/disk0 3 ~/Documents/Virtual\ Machines.localized/Mac_Raw_disk ide
Unable to determine partition start sector(s).
<USER>/Library/Application Support/VMware Fusion $ ./vmware./vmware-rawdiskCreator print /dev/disk0
Nr Start Size Type Id Sytem
1 1 976773167 BIOS EE Unknown