As noted in the Known Issues section of the VMWare Fusion Release Notes, the VMWare Fusion BIOS goes by way too fast to give you a chance to access it. The only way you can access it is by modifying the .vmx configuration file for the VM:
The VMware Fusion BIOS posts too quickly to access.
Most users will not need to access the BIOS, but advanced users might want to do so, to change the boot order, set a boot password, or enable a second floppy drive. To work around this problem, use a text editor to add the following line to the configuration (.vmx) file of the virtual machine:
bios.forceSetupOnce = "TRUE"
The next time you boot up the virtual machine, it will automatically boot into the BIOS. This configuration option then reverts to FALSE. You must set the option to TRUE each time you want to boot the virtual machine into the BIOS.
Having trouble finding the .vmx file?
You cannot edit the .vmx file by opening it with Finder. You need to use the Terminal to edit the file. Here's how you do that:
Launch Terminal (Applications -> Utilities -> Terminal.app) and navigate to the folder (or directory) where your Virtual Machines are stored. To do this, you use the "cd" command. For example, my Virtual Machines are stored in Documents -> Virtual Machines, so I type the following to change into that directory:
cd Documents/Virtual Machines/ and then press Enter.
Now you need to change into the directory that matches the name of your Virtual Machine. For example, let's say it's called "Windows XP" -- you would type
cd Windows XP/. (Note that you have to "escape" spaces in the folder name by preceding them with a backslash.)
Once you're there, you can use the "ls" command (that's a lowercase L) to list the contents of that folder. You should see the .vmx file you're looking for. Now to edit that file in TextEdit, simply run the following command:
open -e *.vmx.
That's it! Now you can edit the file as described above to enable the BIOS.