because of 64-bit requiremeents for Windows (sort of like those for Mountain Lion) to have 64-bit kernel and 64-bit fiirmware
Apple's implementation and it differs from Intel and Microsoft for EFI 64-bit but that is beyond the scope.
you can use a VM. You can use 32-bit. You can try to find how to modify the DVD to allow booting the installer.
yup i install boot camp x64
and here is the way to install
There was an additional step I needed to do. When trying to run BootCamp64.msi I got an error message saying I needed elevate privileges to run this file, and that I should run it through setup.exe (grr). To get around this I,
1) Pressed Shift-rightClick on BootCamp64.msi and
2) Selected the "Copy as path" option from the popup menu.
3) Left click the start button
4) Type cmd in the run text field
5) Right click CMD icon that will be in the popup menu
6) Select "run as administrator", this will open up the command prompt window
7) Right click on the command prompt window and select "Paste"
Worked like a charm